Laser scanner

ABSTRACT

A laser scanner and a system with a laser scanner for measuring an environment. The laser scanner includes an optical distance measuring device, a support, a beam steering unit rotatably fixed to the support which rotates around a beam axis of rotation. The beam steering unit includes a mirrored surface which deflects radiation used in the optical distance measurement and an angle encoder for recording angle data. The optical distance measurement is performed by a progressive rotation of the beam steering unit about the beam axis of rotation and the continuous emission of a distance measurement radiation, the emission being made through an outlet area arranged in the direction of the mirrored surface on the support, the receiving optics for receiving radiation are arranged on the support, and wherein the outlet area has a lateral offset with respect to the optical axis of the receiving optics.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to PCT Application PCT/EP2016/077372,filed on Nov. 10, 2016. The foregoing patent application areincorporated herein by reference.

FIELD OF INVENTION

The invention relates to a laser scanner for optical measurement and forimaging an environment, in particular for generating and displaying acolored 3D point cloud.

BACKGROUND

A three-dimensional measurement of rooms and environments is of greatinterest to craftsmen and architects, for example, since this allows anactual condition and/or the construction progress of rooms or aconstruction site to be rapidly captured so that pending work can bescheduled. By means of a visual display in the form of a point cloud,for example in combination with multiple temporal levels using anaugmented reality and/or in the form of a virtual reality, differentoptions for further steps or extension possibilities can then bereviewed and, if necessary, presented to a colleague or customer in asimple manner.

An environment can be optically scanned and measured using a laserscanner. A common approach to this involves a scanning of theenvironment by means of pulsed electromagnetic radiation, e.g. laserlight, wherein an echo is received from a back-scattering surface pointof the environment and, for example, on the basis of the transit time,the shape, and/or the phase of the pulse a distance to the surface pointis derived and in each case associated with the spatial position of thesurface point, for example using angle information at the time of themeasurement and using the known location of the laser scanner.

Significant differences in the design of a laser scanner are obtained,in particular due to whether the laser scanner is intended for anoptical scanning process in the form of a raster scanning or in the formof a scanning sensing, wherein the present invention relates mainly toscanning laser scanners, specifically to laser scanners with a beamdeflection unit rotating at high speed.

In the case of a raster scanning the optical sensing takes place, forexample, by means of a specific individual sensing of a plurality ofsurface points, for example on the basis of a predefined scanning rasterfor the environment to be scanned, in other words by using specifictargeting of individual predefined raster points.

In the case of a scanned sensing typically by means of at least onerotating beam deflection element for variation of the alignment of theemission direction of the distance measurement beam, e.g. a plane mirrorinclined with respect to an axis of rotation, a plurality of measuringpoints is recorded and spatially measured, wherein, for example, adesired point-to-point resolution is achieved by adjustment of the pulserate of the distance measurement beam and/or by adjusting the rotationalspeed of the beam deflection element. The environment can then beanalyzed and/or displayed in different ways based on the plurality ofmeasurement points using common data processing steps and/or displaymethods, in particular as a 3D point cloud.

Typically, scanning laser scanners have one or two mutually orthogonalaxes of rotation, for example a vertical axis of rotation for acomparatively slow rotation of the entire laser scanner, often alsoreferred to as “azimuth axis” or “slow axis”, and a horizontal axis ofrotation perpendicular thereto for a high-speed rotating beam deflectionelement. Due to the high rotation speeds of the beam deflection elementfrequently used, the second axis is also referred to as “the fast axis”.

For a sensing of linear or linearly moveable structures andenvironments, such as, for example, railway track systems, roads,tunnels systems or air fields, instead of a rotation around the azimuthaxis a translational motion of the entire laser scanner is oftenutilized, for example, by the laser scanner being mounted on a vehicle.Such laser scanners, which only have the fast axis, are also known asprofilers.

Such laser scanners with a fast axis, and possibly with an azimuth axisor in combination with a translational motion, enable a user to senselarge surfaces and objects in a relatively small period of time.

For additional information, the information and scanning data can becombined and processed, for example, with camera data, in particular RGBcamera data or infrared data.

In some cases, distance measurement modules used in laser scanners forspatial measurement have an intensity sensitivity but no colorsensitivity, which means the 3D point cloud generated can be displayedin grayscale levels without the need to use additional data. Using areferencing of the “gray” 3D point cloud with RGB data from a colorcamera, for example a “colored” 3D point cloud can be generated, whichmakes, for example, its display considerably easier to the human eye.The referencing of different data and data sets, such as those fromtemporally and spatially varying measurement procedures, is nowadaysincreasingly standardized.

Laser scanners can also be designed with a position and orientationsystem, for example by means of an inertial system, tilt sensors or areceiver for a global satellite navigation system, for example whereinlocal sensing data are automatically referenced with a global 3Dcoordinate system.

SUMMARY

An object of some aspects of the invention is to provide an improvedlaser scanner and an improved system for measuring and for imaging anenvironment by means of a laser scanner.

This object is achieved by the implementation of the characterizingfeatures of the independent claims. Features that extend the inventionin alternative or more advantageous ways are contained in the dependentclaims.

Some aspects of the invention relate to a measurement system for opticalmeasurement and for imaging an environment, with a laser scanner forcollecting measurement data, a processing unit for processing parts ofthe measurement data into processed measurement data, and with a displayfor displaying portions of the processed measurement data whichrepresent at least a partial region of the environment; wherein thelaser scanner comprises an optical distance measuring device fordetecting distance measurement data, with a transmitter unit foremitting a distance measurement radiation and a receiver unit forreceiving returning parts of the distance measurement radiation, asurface sensor for detecting surface sensor data, in particular, atleast one color camera for recording image data, wherein the sensordefines an optical axis of the sensor and a viewing direction of thesensor along the optical axis, a base, a support which is fixed to thebase such that it can rotate about a support axis of rotation, inparticular a slow axis of rotation, a beam steering unit for thedistance measurement radiation which is fixed to the support such thatit can rotate about a beam axis of rotation, in particular a fast axisof rotation, substantially orthogonal to the support axis of rotation, afirst angle encoder for detecting data relating to a first rotation ofthe support about the support axis of rotation and a second angleencoder for detecting data relating to a rotation of the beam steeringunit about the beam axis of rotation, wherein the distance measurementdata, the surface sensor data and the first and second angle data,hereafter designated as measurement data, (wherein the distancemeasurement data in combination with the first and second angle data areoften also referred to as sampled measurement data) are detected duringa measurement process which comprises a scanning sensing by means of thedistance measuring device with a defined progressive, in particularcontinuous, rotation of the support about the support axis of rotation,with a defined progressive, in particular continuous, rotation of thebeam steering unit about the beam axis of rotation, and with acontinuous emission of the distance measurement radiation and acontinuous reception of returning parts of the distance measurementradiation, and multiple reading of the surface sensor with respect todifferent viewing directions of the sensor.

One aspect of some embodiments of the invention relate, for example, tothe fact that the processing unit is arranged on a separate computingdevice from the laser scanner, in particular a computer or tablet, andthe laser scanner and the computing device are configured in such a waythat a transmission of the measurement data from the laser scanner tothe computing device takes place, in particular wirelessly, specificallyby means of a WLAN or Bluetooth connection, an at least initialprocessing of the parts of the measurement data in terms of anassociation of the surface sensor data with the distance measurementdata and the first and second angle data takes place during themeasurement process, and the display of portions of the processedmeasurement data takes place during the measurement process and isprogressively, in particular continuously, updated based on theprocessed measurement data, in particular supplemented and/or replaced,specifically wherein a display coupled or integrated with the computingdevice is provided for the display.

One embodiment relates, for example, to the fact that by means of avirtual 360-degree rotation of the beam steering unit about the beamaxis of rotation a scanning plane of the distance measurement radiationis defined, and the surface sensor is arranged and oriented on thesupport in such a way that its azimuthal viewing direction and theazimuthal orientation of the scanning plane are different, which meansthat a virtual backwards extension of the optical axis of the surfacesensor cuts the scanning plane under a defined cutting angle, inparticular wherein the cutting angle is at least 45 degrees,specifically wherein the scanning plane is not captured by the field ofview of the surface sensor, wherein a fully automated firstpre-programmed measurement process with defined steps is carried outaccording to the following temporal sequence:

-   -   providing surface sensor data comprising        -   rotation of the support about the support axis of rotation,        -   reading from the surface sensor for detecting surface sensor            data, and        -   data streaming of a portion of the detected surface sensor            data to the computing device,    -   in particular, wherein an initial processing and display of the        detected surface sensor data is carried out based on the data        streaming,    -   providing scanning measurement data, namely distance measurement        data and associated first and second angle data, comprising,        -   rotation of the support about the support axis of rotation,        -   rotation of the beam steering unit about the beam axis of            rotation,        -   emitting the distance measurement radiation and receiving            returning parts of the distance measurement radiation for            detecting distance measurement data, wherein associated            first and second angle data are detected during the            detection of distance measurement data, and        -   data streaming of a portion of the detected scanning            measurement data to the computing device,    -   initial processing of the parts of the surface sensor data and        scanning measurement data transmitted by means of data        streaming, and    -   displaying the parts of the surface sensor data and scanning        measurement data associated by means of data streaming in the        form of a colored 3D point cloud.

A further embodiment relates to the fact that a second pre-programmedmeasurement process is carried out with a defined temporal sequence ofthe following steps:

-   -   providing a first set of surface sensor data, in particular        surface sensor data with reduced resolution, comprising        -   rotation of the support about the support axis of rotation,        -   reading from the surface sensor for detecting surface sensor            data, and        -   data streaming of a portion of the detected surface sensor            data to the computing device,    -   in particular, wherein an initial processing and display of the        first set of surface sensor data is carried out based on the        data streaming,    -   deriving a set of exposure times of the surface sensors based on        the first set of surface sensor data, and    -   providing a second set of surface sensor data based on the set        of exposure times of the surface sensors, comprising        -   rotation of the support about the support axis of rotation,        -   reading from the surface sensor for detecting surface sensor            data, and        -   data streaming of a portion of the detected surface sensor            data to the computing device,    -   in particular, wherein based on the data streaming, an initial        processing and display of the second set of surface sensor data        is carried out.

A further embodiment relates to the fact that a third pre-programmedmeasurement process is carried out with a defined temporal sequence ofthe following steps:

-   -   providing surface sensor data comprising        -   rotation of the support about the support axis of rotation,        -   reading from the surface sensor for detecting surface sensor            data, in particular wherein the detection of the surface            sensor data comprises a data processing of exclusively read            out, namely unprocessed, surface sensor raw data, and        -   data streaming of a portion of the detected surface sensor            data to the computing device,    -   in particular, wherein an initial processing and display of the        detected surface sensor data is carried out based on the data        streaming,    -   providing scanning measurement data comprising,        -   rotation of the support about the support axis of rotation,        -   rotation of the beam steering unit about the beam axis of            rotation,        -   emitting the distance measurement radiation and receiving            returning parts of the distance measurement radiation for            detecting distance measurement data, wherein associated            first and second angle data are detected during the            detection of distance measurement data, and the detection of            the distance measurement data comprises a data processing of            exclusively received, namely unprocessed, surface sensor raw            data, and        -   data streaming of a portion of the detected scanning            measurement data to the computing device,    -   initial processing of the parts of the surface sensor data and        scanning measurement data transmitted by means of data        streaming, and    -   displaying the parts of the surface sensor data and scanning        measurement data associated by means of data streaming in the        form of a colored 3D point cloud.    -   in particular, wherein the data processing of the distance        measurement raw data comprises a consideration of parameters        dependent on the first and/or second angle data as part of        referencing the measurement data with respect to a common        coordinate system.

A further embodiment relates to the fact that the laser scanner and thecomputing device are configured in such a way that by means of amonitoring and control unit on the computing device, control signals canbe transmitted to the laser scanner, in particular wirelessly,specifically by means of a WLAN or Bluetooth connection.

A further embodiment relates to the fact that the computing device isequipped with an inertial measurement system and/or tilt sensors, sothat on the basis of a location of the computing device, in particular aposition and/or orientation, an adjustment of a rotational position ofthe support about the support axis of rotation and/or an adjustment of arotational position of the beam steering unit about the beam axis ofrotation is carried out, in particular substantially synchronously witha change in position of the computing device, in particular wherein byadjustment of at least a first position of the computing device at leastone region of interest of the environment can be defined, in particularwherein settings defined for the at least one region of interest for thedetection of measurement data and/or defined settings for the display ofparts of the processed measurement data can be made, in particularwherein the defined setting for the detection of measurement datacomprises a measurement resolution of the surface sensor and/or ameasurement accuracy of the distance measuring device and/or a scanningresolution of the distance measuring device, and/or the defined settingfor the display of portions of the processed measurement data comprisesa display resolution and/or a color setting and/or a gray value settingand/or a defined highlighting relative to a sub-region within the regionof interest.

A further embodiment relates to the fact that the computing device isconfigured in such a way that auxiliary data can be accessed forprocessing the measurement data and/or displaying portions of theprocessed measurement data, in particular wherein the auxiliary data areinvoked for a visual display in the form of an augmented reality and/orin the form of a virtual reality.

A further embodiment relates to the fact that the laser scannercomprises a position determination unit for providing referencing data,in particular position and/or orientation of the laser scanner unit,having at least one element of the following group: an inertialmeasurement system, a tilt sensor for detecting at least one tilt withrespect to the direction of gravity, a receiver for a global satellitenavigation system and/or for a pseudo-satellite navigation system, acompass, in particular an electronic compass, and a barometer, whereinthe measurement data also include the referencing information, and/orthe data processing is based on a procedure for simultaneouslocalization and mapping (SLAM).

A further aspect of some embodiments of the invention, taken separatelyor in combination with the other embodiments of the invention, relate toa laser scanner for optical measurement of an environment, comprising anoptical distance measuring device for the detection of distancemeasurement data, with a transmitter unit for emitting a distancemeasurement radiation and a receiver unit for receiving returning partsof the distance measurement radiation, a surface sensor for detectingsurface sensor data, in particular at least one color camera forrecording image data, wherein the sensor defines an optical axis of thesensor and a viewing direction of the sensor along the optical axis, abase, a support which is fixed to the base such that it can rotate abouta support axis of rotation, in particular a slow axis of rotation, abeam steering unit for the distance measurement radiation which is fixedto the support such that it can rotate about a beam axis of rotation, inparticular a fast axis of rotation, substantially orthogonal to thesupport axis of rotation, a first angle encoder for detecting datarelating to a first rotation of the support about the support axis ofrotation and a second angle encoder for detecting data relating to arotation of the beam steering unit about the beam axis of rotation,wherein the distance measurement data, the surface sensor data and thefirst and second angle data, hereafter referred to as measurement data,are detected as part of a measurement process which comprises a scanningsensing by means of the distance measuring device with a definedprogressive, in particular continuous, rotation of the support about thesupport axis of rotation, with a defined progressive, in particularcontinuous, rotation of the beam steering unit about the beam axis ofrotation, and with a continuous emission of the distance measurementradiation and a continuous reception of returning parts of the distancemeasurement radiation, and multiple reading of the surface sensor withrespect to different viewing directions of the sensor.

The aspect of some embodiments of the invention is characterized in thatby means of a virtual 360-degree rotation of the beam steering unitabout the beam axis of rotation a scanning plane of the distancemeasurement radiation is defined, and the surface sensor is arranged andoriented on the support in such a way that its azimuthal viewingdirection and the azimuthal orientation of the scanning plane aredifferent, in the sense that a virtual backwards extension of theoptical axis of the surface sensor cuts the scanning plane under adefined cutting angle, in particular wherein the cutting angle is atleast 45 degrees, specifically wherein the scanning plane is notcaptured by the field of view of the surface sensor, wherein a fullyautomated first pre-programmed measurement process with defined steps iscarried out according to the following temporal sequence:

-   -   recording of surface sensor data comprising        -   rotation of the support about the support axis of rotation,            and        -   reading out the surface sensor for detecting surface sensor            data, in particular, wherein an initial processing and            display of the surface sensor data is carried out,    -   recording of scanning measurement data, namely distance        measurement data and associated first and second angle data,        comprising,        -   rotation of the support about the support axis of rotation,        -   rotation of the beam steering unit about the beam axis of            rotation, and        -   emitting the distance measurement radiation and receiving            returning parts of the distance measurement radiation for            detecting distance measurement data, wherein associated            first and second angle data are detected during the            detection of distance measurement data.

One embodiment relates to the fact that a second pre-programmedmeasurement process with defined steps is carried out according to thefollowing temporal sequence:

-   -   providing a first set of surface sensor data, in particular        surface sensor data with reduced resolution, comprising        -   rotation of the support about the support axis of rotation,            and        -   reading out the surface sensor for detecting surface sensor            data,    -   derivation of a surface sensor exposure time based on the first        set of surface sensor data, and    -   providing a second set of surface sensor data, based on the        exposure time of the surface sensor, comprising        -   rotation of the support about the support axis of rotation,            and        -   reading from the surface sensor for detecting surface sensor            data,

A further embodiment relates to the fact that an at least initialprocessing of parts of the measurement data is performed during themeasurement process, in particular an association of the sampledmeasurement data and the surface sensor data, in particular wherein thedisplay of portions of the processed measurement data takes place duringthe measurement process and is progressively, in particularcontinuously, updated based on the processed measurement data, inparticular supplemented and/or replaced, specifically wherein a displaycoupled or integrated with the laser scanner is provided for thedisplay.

A further embodiment relates to the fact that based on the surfacesensor data at least one region of interest of the environment can bedefined, in particular wherein for the at least one region of interest,defined settings for the detection of measurement data and/or definedsettings for the display of portions of the processed measurement datacan be made.

A further embodiment relates to the fact that as part of the measurementprocess a complete detection of all surface sensor data required for themeasurement process takes place before the acquisition of sampledmeasured data begins, in particular wherein based on the detectedsurface sensor data a 2D panorama display of at least one partial regionof the environment is generated, or a 2D full-dome projection isgenerated.

A further aspect of some embodiments of the invention, taken alone or incombination with the other embodiments of the invention, relate to ameasurement system for optical measurement of an environment, having alaser scanner for the collection of measurement data, a processing unitfor processing of parts of the measurement data into processedmeasurement data, and a display unit for a defined display of portionsof the processed measurement data which represent at least a partialregion of the environment, wherein the laser scanner comprises anoptical distance measuring device for recording distance measurementdata, with a transmitter unit for emitting a distance measurementradiation and a receiver unit for receiving returning parts of thedistance measurement radiation, a support, a beam steering unit for thedistance measurement radiation, which is fixed to the support such thatit can rotate about a beam axis of rotation, in particular a fast axisof rotation, an angle encoder for detecting data relating to a rotationof the beam steering unit about the beam axis of rotation, wherein themeasurement data comprise the distance measurement data and the angledata.

The aspect of the embodiment of invention is characterized in that acentral reference point of the laser scanner is defined as the originfor distance and angle measurement, in particular by the intersectionpoint of the beam axis of rotation with a support axis of rotation for arotation of the support about a base, an infrared sensor sensitive inthe infrared wavelength range is integrally arranged on the support,wherein the infrared sensor defines an optical axis of the infraredsensor and a viewing direction of the infrared sensor along the opticalaxis, and a position of the infrared sensor and an orientation of itsoptical axis with respect to the beam steering unit and the centralreference point is known, the measurement data comprise infrared datadetected with the infrared sensor, and the measurement data areassociated with the infrared data, in particular so that temperatureinformation is taken into account for the display of portions of theprocessed data.

A further embodiment relates to the fact that the display of portions ofthe processed measurement data is generated in the form of a colored 3Dpoint cloud and the temperature information is stored in the 3D pointcloud and/or displayed with a defined color coding.

A further aspect of the invention, taken either alone or in combinationwith the previously mentioned aspect of the invention, relates to alaser scanner for optical measurement of an environment, comprising anoptical distance measuring device for detecting distance measurementdata, having a transmitter unit for emitting a distance measurementradiation and a receiver unit for receiving returning parts of thedistance measurement radiation, a support, a beam steering unit for thedistance measurement radiation, which is fixed to the support such thatit can rotate around a beam axis of rotation, in particular a fast axisof rotation, and an angle encoder for detecting angle data with respectto a rotation of the beam steering unit about the beam axis of rotation,wherein the distance measurement data and the angle data, hereafterdesignated as measurement data, are detected during a measurementprocess which comprises a scanning sensing by means of the distancemeasuring device with a defined progressive, in particular continuous,rotation of the beam steering unit about the beam axis of rotation, andwith a continuous emission of the distance measurement radiation and acontinuous reception of returning parts of the distance measurementradiation.

The aspect of this embodiment the invention is characterized in that thelaser scanner only has a single integrated control element (e.g. asingle button, also in the form of a touch-screen button or a singleswitch), the control element has only a single active and a singleinactive state and can be switched by way of an external action in orderto occupy the active or inactive state, a set of defined measurementprograms and/or actions of the laser scanner is stored, and individualmeasurement programs and/or actions from the set of defined measurementprograms and/or actions are triggered based on at least one element fromthe following group:

-   -   change of the state of the control element from the inactive to        the active state,    -   change of the state of the control element from the active to        the inactive state,    -   switching of the control element by means of a persistent        external action during a defined time interval,    -   a coded sequence of state changes of the control element between        the active and inactive state, and    -   a coded sequence of temporally persistent external actions on        the control element over defined time intervals.

One embodiment relates for example to the fact that the set of definedmeasurement programs and/or actions of the laser scanner comprisesactivating the laser scanner, as well as at least one element from thefollowing group: deactivation of the laser scanner, starting themeasurement process, interrupting the measurement process, aborting themeasurement process and restarting the measurement process; inparticular, wherein a set of different settings for the measurementprocess is stored and/or can be defined and the set of definedmeasurement programs and/or actions of the laser scanner unit alsocomprises at least one element of the following group: adjusting asetting from the set of settings for the measurement process, startingthe measurement process with a setting from the set of settings for themeasurement process, and restoring a default setting of the laserscanner, in particular a default startup configuration of the laserscanner.

A further embodiment relates, for example, to the fact that the codedsequence of state changes of the control element is defined by adefinite number of state changes during a defined time interval betweenthe active and inactive state, and/or the coded sequence of temporallypersistent external actions is defined by one or more differentlydefined time intervals for maintaining the external action.

A further aspect of some embodiments of the invention, taken eitheralone or in combination with the other embodiments of the invention,relate to a laser scanner for optical measurement of an environment,comprising an optical distance measuring device for detecting distancemeasurement data, having a transmitter unit for emitting a distancemeasurement radiation and a receiver unit for receiving returning partsof the distance measurement radiation, a surface sensor for detectingsurface sensor data, in particular at least one color camera forrecording image data, wherein the sensor defines an optical axis of thesensor and a viewing direction of the sensor along the optical axis, asupport, a beam steering unit for the distance measurement radiation,which is fixed to the support such that it can rotate around a beam axisof rotation, in particular a fast axis of rotation, an angle encoder fordetecting angle data with respect to a rotation of the beam steeringunit about the beam axis of rotation, wherein the distance measurementdata, the surface sensor data and the first and second angle data,hereafter designated as measurement data, are detected during ameasurement process which comprises a scanning sensing by means of thedistance measuring device with a defined progressive, in particularcontinuous, rotation of the beam steering unit about the fast axis ofrotation, and with a continuous emission of the distance measurementradiation and a continuous reception of returning parts of the distancemeasurement radiation, and multiple readings of the surface sensor withrespect to different viewing directions of the sensor.

The aspect of some embodiments of the invention is characterized in thata central reference point of the laser scanner is defined as the originfor distance and angle measurement, in particular by the intersectionpoint of the beam axis of rotation with a support axis of rotation for arotation of the support about a base, the surface sensor being fixedlyarranged on the support with a stationary field of view relative to thesupport and facing away from the support, in the sense that the field ofview of the sensor changes during the measurement process only in theevent of a movement of the support, in particular a rotation of thesupport about the beam axis of rotation, and a virtual backwardextension of the optical axis of the surface sensor passes through thecentral reference point.

One embodiment relates for example to the fact that a multiplicity ofsurface sensors is arranged on the support, wherein for each one of themultiplicity of surface sensors the virtual backward extension of itsoptical axis substantially passes through the central reference point.

A further embodiment relates for example to the fact that a scanningplane of the distance measurement radiation is defined by a virtual360-degree rotation of the beam steering unit about the beam axis ofrotation, and one of the multiplicity of surface sensors is arranged insuch a way that its visual field cone intersects the scanning plane, inparticular wherein the support is fixed on a base such that it canrotate about a support axis of rotation, in particular a slow axis ofrotation, and the visual field cone of the surface sensor intersectswith the steepest elevational orientation of the optical axis with avirtual extension of the support axis of rotation.

A further embodiment relates, for example, to the fact that the supportis fixed on a base such that it can rotate about a support axis ofrotation, in particular a slow axis of rotation, the laser scannercomprises a further angle encoder for detecting further angle data asmeasurement data relating to a rotation of the support about the supportaxis of rotation, the measurement also comprises multiple readings fromthe multiplicity of surface sensors with respect to different azimuthalviewing directions of the individual sensors, and the multiplicity ofsurface sensors are arranged in such a way that during the measurementprocess they enable a full-dome measurement, in particular wherein thevisual field cone of the surface sensor intersects with the steepestelevational orientation of the optical axis with a virtual extension ofthe support axis of rotation, wherein the multiplicity of surfacesensors define a minimum detection radius for the full-dome measurementin such a way that a spherical surface is defined by the centralreference point and the minimum detection radius with the centralreference point at the center, and during the measurement process atleast one hemispherical surface defined by the spherical surface canonly just be scanned by the multiplicity of surface sensors, inparticular wherein by means of the multiplicity of surface sensors apartial surface of the sphere can be scanned that is larger than thehemispherical surface.

A further aspect of some embodiments of the invention, taken eitheralone or in combination with the other embodiments of the invention,relate to a laser scanner for optical measurement of an environment,comprising an optical distance measuring device for detecting distancemeasurement data, having a transmitter unit for emitting a distancemeasurement radiation and a receiver unit for receiving returning partsof the distance measurement radiation, a surface sensor for detectingsurface sensor data, in particular at least one color camera forrecording image data, wherein the sensor defines an optical axis of thesensor and a viewing direction of the sensor along the optical axis, asupport, a beam steering unit for the distance measurement radiation,which is fixed to the support such that it can rotate around a beam axisof rotation, in particular a fast axis of rotation, an angle encoder fordetecting angle data with respect to a rotation of the beam steeringunit about the beam axis of rotation, wherein the distance measurementdata, the surface sensor data and the first and second angle data,hereafter designated as measurement data, are detected during ameasurement process which comprises a scanning sensing by means of thedistance measuring device with a defined progressive, in particularcontinuous, rotation of the beam steering unit about the fast axis ofrotation, and with a continuous emission of the distance measurementradiation and a continuous reception of returning parts of the distancemeasurement radiation, and multiple readings of the surface sensor withrespect to different viewing directions of the sensor.

The aspect of some embodiments of the invention is characterized in thata central reference point of the laser scanner is defined as the originfor distance and angle measurement, in particular by the intersectionpoint of the beam axis of rotation with a support axis of rotation for arotation of the support about a base, a multiplicity of surface sensorswith different elevational orientation of the optical axis are fixedlyarranged on the support, in the sense that the fields of view of thesensors during the measurement process only change in the event of amovement of the support, in particular a rotation of the support aboutthe beam axis of rotation, and for each one of the plurality of surfacesensors the virtual backwards extension of its optical axissubstantially passes through the central reference point.

One embodiment relates for example to the fact that the multiplicity ofsurface sensors are arranged with the same azimuthal direction, inparticular wherein a scanning plane of the distance measurementradiation is defined by means of a virtual 360-degree rotation of thebeam steering unit about the beam axis of rotation and the optical axesof the multiplicity of surface sensors are arranged in a plane outsidethe scanning plane.

A further embodiment relates, for example, to the fact that the visualfield cone of the surface sensor with the steepest elevation orientationof the optical axis intersects with the scanning plane at a distance ofbetween 0.25 and 7 m from the central reference point.

A further aspect of the invention, taken either alone or in combinationwith the other aspects of the invention, relates to a laser scanner foroptical measurement of an environment, comprising an optical distancemeasuring device for detecting distance measurement data, having atransmitter unit for emitting a distance measurement radiation and areceiver unit for receiving returning parts of the distance measurementradiation, a surface sensor for detecting surface sensor data, inparticular at least one color camera for recording image data, whereinthe sensor defines an optical axis of the sensor and a viewing directionof the sensor along the optical axis, a support, a beam steering unitfor the distance measurement radiation, which is fixed to the supportsuch that it can rotate around a beam axis of rotation, in particular afast axis of rotation, an angle encoder for detecting angle data withrespect to a rotation of the beam steering unit about the beam axis ofrotation, wherein the distance measurement data, the surface sensor dataand the first and second angle data, hereafter designated as measurementdata, are detected during a measurement process which comprises ascanning sensing by means of the distance measuring device with adefined progressive, in particular continuous, rotation of the beamsteering unit about the fast axis of rotation, and with a continuousemission of the distance measurement radiation and a continuousreception of returning parts of the distance measurement radiation, andmultiple readings of the surface sensor with respect to differentviewing directions of the sensor.

The aspect of some embodiments of the invention is characterized in thatthe laser scanner comprises a lamp illuminating the field of view of thesurface sensor, in particular one or more LEDs, wherein the lamp definesan optical axis of the lamp and an illumination direction of the lampalong the optical axis of the lamp, and the lamp is used for aselectively controllable illumination, substantially directed onto thefield of view of the surface sensor.

One embodiment relates, for example, to the fact that the surface sensoris arranged on the support and the lamp is arranged on the supportdirectly next to the surface sensor, in particular with a maximumlateral offset between the optical axis of the lamp and the optical axisof the surface sensor of 4 cm.

A further embodiment relates, for example, to the fact that the lampsubstantially emits white light, which means broadband light in thevisible wavelength range, in particular by the lamp being designed as adual LED, namely an LED couplet with two separate LEDs differing withrespect to their emitted spectral range.

A further embodiment relates, for example, to the fact that amultiplicity of surface sensors is arranged on the support, wherein eachof the multiplicity of surface sensors is assigned controllable lampsspecific to said sensor, substantially illuminating the field of view ofsaid sensor.

A further embodiment relates, for example, to the fact that a first setof surface sensor data is detected, in particular surface sensor datawith reduced resolution, a set of illumination settings for the lamp isderived based on the first set of surface sensor data, and a second setof surface sensor data is recorded based on the set of illuminationsettings, in particular wherein the first set of surface sensor data isdetected without using the lamp or else using a uniform illumination bythe lamp.

A further aspect of some embodiments of the invention, taken separatelyor in combination with the other embodiments of the invention, relate toa laser scanner for optical measurement of an environment, comprising anoptical distance measuring device for the detection of distancemeasurement data, with a transmitter unit for emitting a distancemeasurement radiation and a receiver unit for receiving returning partsof the distance measurement radiation, a base, a support which is fixedto the base such that it can rotate about a support axis of rotation, inparticular a slow axis of rotation, a beam steering unit for thedistance measurement radiation which is fixed to the support such thatit can rotate about a beam axis of rotation, in particular a fast axisof rotation, substantially orthogonal to the support axis of rotation, afirst angle encoder for detecting data relating to a first rotation ofthe support about the support axis of rotation and a second angleencoder for detecting data relating to a rotation of the beam steeringunit about the beam axis of rotation, wherein the distance measurementdata and the first and second angle data, hereafter referred to asmeasurement data, are detected as part of a measurement process whichcomprises a scanning sensing by means of the distance measuring devicewith a defined progressive, in particular continuous, rotation of thesupport about the support axis of rotation, with a defined progressive,in particular continuous, rotation of the beam steering unit about thebeam axis of rotation, and with a continuous emission of the distancemeasurement radiation and a continuous reception of returning parts ofthe distance measurement radiation.

The aspect of some embodiments of the invention is characterized in thatthe base comprises only one overall effective stabilization regionaxially along the support axis of rotation, which is used to stabilizethe support against a tilting of the support relative to the base, thestabilization region has a first extension axially along the supportaxis of rotation and a second extension perpendicular to the supportaxis of rotation and substantially radially symmetric with respect tothe support axis of rotation, and the second extension is larger thanthe first extension.

One embodiment relates, for example, to the fact that the support ismounted by means of a single bearing rim such that it can pivot relativeto the base about the support axis of rotation, wherein thestabilization is achieved exclusively by the single bearing rim.

A further embodiment relates, for example, to the fact that the bearingrim is designed as a single-row four-point roller bearing, or thebearing rim is designed as a single-row sliding bearing with an outerand inner ring and the outer ring forms two contact bearings with theinner ring, in particular two bearing lines or two bearing surfaces,axially spaced apart with respect to the support axis of rotation.

A further embodiment relates, for example, to the fact that thestabilization is generated by means of a spring loading acting radiallyon the bearing rim with respect to the support axis of rotation.

A further embodiment relates, for example, to the fact that the secondextension is greater than the first extension by at least a factor oftwo, in particular wherein the second extension is greater than thefirst extension by at least a factor of five, specifically wherein thesecond extension is greater than the first extension by at least afactor of ten.

A further embodiment relates, for example, to the fact that alubricant-repellent emulsion is applied along a boundary regionsubstantially parallel to a contact bearing, so that a dispersion of alubricant for the bearing rim due to the surface tension of thelubricant-repellent emulsion is substantially limited by the boundaryregion, or the bearing rim is designed as a four-point roller bearing inthe form of a dry-running ring bearing with ceramic roller elements.

A further aspect of the invention, taken separately or in combinationwith the other aspects of the invention, relates to a laser scanner foroptical measurement of an environment, comprising an optical distancemeasuring device for the detection of distance measurement data, with atransmitter unit for emitting a distance measurement radiation and areceiver unit for receiving returning parts of the distance measurementradiation, a base, a support which is fixed to the base such that it canrotate about a support axis of rotation, in particular a slow axis ofrotation, a beam steering unit for the distance measurement radiationwhich is fixed to the support such that it can rotate about a beam axisof rotation, in particular a fast axis of rotation, substantiallyorthogonal to the support axis of rotation, a first angle encoder fordetecting data relating to a first rotation of the support about thesupport axis of rotation and a second angle encoder for detecting datarelating to a rotation of the beam steering unit about the beam axis ofrotation, wherein the distance measurement data and the first and secondangle data, hereafter referred to as measurement data, are detected aspart of a measurement process which comprises a scanning sensing bymeans of the distance measuring device with a defined progressive, inparticular continuous, rotation of the support about the support axis ofrotation, with a defined progressive, in particular continuous, rotationof the beam steering unit about the beam axis of rotation, and with acontinuous emission of the distance measurement radiation and acontinuous reception of returning parts of the distance measurementradiation.

The aspect of some embodiments of the invention is characterized inthat, with respect to a rotation of the support about the support axisof rotation the base is designed exclusively as a passive element, inthe sense that all active electronics required for the motorization ofthe rotation around the support axis of rotation is arranged exclusivelyin the support and co-rotates with the support around the axis ofrotation of the support, in particular wherein each of the followingcomponents is arranged entirely in the support and co-rotates with thesupport about the support axis of rotation: an active drive element forthe rotation of the support about the support axis of rotation, inparticular a rotary motor with a drive shaft coupled to the motor or anelectrical coil element for a radial interaction with respect to thesupport axis of rotation between the electrical coil element and apassive magnetic element in the base, and a power supply unit for theactive drive element.

One embodiment relates, for example, to the fact that for the rotationof the support about the support axis of rotation, a rotary motorarranged in the support is designed with a drive shaft coupled to themotor, the drive shaft runs axially with an offset relative to thesupport axis of rotation substantially parallel to the support axis ofrotation, the base comprises a circular symmetrical bearing surfacearound the support axis of rotation, an idle wheel is arranged on thedrive shaft, in particular with a rubber ring, which is operativelyconnected to the bearing surface in such a way that during rotation ofthe drive shaft the idle wheel runs along the bearing surface and thesupport therefore rotates about the support axis of rotation withrespect to the base, in particular wherein the bearing surface defines avirtual circle and the idle wheel is arranged inside the circle.

A further embodiment relates, for example, to the fact that thefollowing components as a whole are additionally arranged in the supportand operated by means of the power supply unit: the optical distancemeasuring device, the surface sensor, a monitoring and control unit, andelectronics of the first and second angle encoders, in particularwherein the base and the support are designed in such a way that duringthe measurement process no electrical power transmission and noelectrical signal transmission takes place between the base and thesupport.

A further embodiment relates, for example, to the fact that the laserscanner comprises a total of only one power supply unit, namely thepower supply unit for the active drive element, which is arranged in thesupport, in particular wherein the base is permanently and irreversiblyelectrically decoupled from the support, such that no electrical powertransmission takes place between the support and the base.

A further embodiment relates, for example, to the fact that the laserscanner comprises a wireless signal transmission unit, in particular,based on a WLAN or Bluetooth connection, wherein the signal transmissionunit as a whole is arranged in the support, wherein a two-waytransmission of measurement data and/or auxiliary data is providedbetween the laser scanner and an external control unit and/or atransmission of a portion of the measurement data from the laser scannerto an external computing and/or storage unit is provided, in particularwherein a two-way transmission of measurement data and/or auxiliary datais provided between the laser scanner and the external computing and/orstorage unit.

A further embodiment relates for example to the fact that thetransmission of the measurement and/or auxiliary data is carried outsubstantially parallel to the measurement process by means of a datastreaming of parts of the measurement data, which is startedsimultaneously with respect to the start of the measurement process, orat least almost simultaneously.

A further aspect of the invention, taken separately or in combinationwith the previously mentioned aspects of the invention, relates to alaser scanner for optical measurement of an environment, comprising anoptical distance measuring device for the detection of distancemeasurement data, with a transmitter unit for emitting a distancemeasurement radiation and a receiver unit for receiving returning partsof the distance measurement radiation, a base, a support which is fixedto the base such that it can rotate about a support axis of rotation, inparticular a slow axis of rotation, a beam steering unit for thedistance measurement radiation which is fixed to the support such thatit can rotate about a beam axis of rotation, in particular a fast axisof rotation, substantially orthogonal to the support axis of rotation, afirst angle encoder for detecting data relating to a first rotation ofthe support about the support axis of rotation, and a second angleencoder for detecting data relating to a rotation of the beam steeringunit about the beam axis of rotation, wherein the distance measurementdata and the first and second angle data, hereafter referred to asmeasurement data, are detected as part of a measurement process whichcomprises: a scanning sensing by means of the distance measuring devicewith a defined progressive, in particular continuous, rotation of thesupport about the support axis of rotation, a defined progressive, inparticular continuous, rotation of the beam steering unit about the beamaxis of rotation, and with a continuous emission of the distancemeasurement radiation and a continuous reception of returning parts ofthe distance measurement radiation.

The aspect of some embodiments of the invention is characterized in thatfor the rotation of the support about the support axis of rotation, arotary motor arranged in the support is designed with a drive shaftcoupled to the motor, the drive shaft runs axially with an offsetrelative to the support axis of rotation substantially parallel to thesupport axis of rotation, the base comprises a circular symmetricalbearing surface around the support axis of rotation, an idle wheel isarranged on the drive shaft, in particular with a rubber ring, which isoperatively connected to the bearing surface in such a way that duringrotation of the drive shaft the idle wheel runs along the bearingsurface and the support therefore rotates about the support axis ofrotation with respect to the base, in particular wherein the bearingsurface defines a virtual circle and the idle wheel is arranged insidethe circle.

A further aspect of some embodiments of the invention, taken eitheralone or in combination with the previously mentioned embodiments of theinvention, relate to a laser scanner for optical measurement of anenvironment, comprising an optical distance measuring device fordetecting distance measurement data, having a transmitter unit foremitting a distance measurement radiation and a receiver unit forreceiving returning parts of the distance measurement radiation, asupport, a beam steering unit for the distance measurement radiation,which is fixed to the support such that it can rotate around a beam axisof rotation, in particular a fast axis of rotation, and an angle encoderfor recording angle data with respect to a rotation of the beam steeringunit about the beam axis of rotation.

The aspect of some embodiments of the invention is characterized in thatthe beam steering unit is connected to a shaft mounted in the supportconnected along the beam axis of rotation, in particular wherein theshaft penetrates into the beam steering unit with a defined penetrationdepth or is designed integrally with the beam steering unit, abell-shaped element is arranged on the shaft, in particular wherein thebell-shaped element is arranged in a fixed position on the shaft or isformed integrally with the shaft, wherein the bell-shaped elementdefines a bell-shaped body and a bell-shaped back, passive magneticelements of a drive are arranged in the bell-shaped body for rotatingthe shaft, active drive elements of the drive are arranged anchored inthe support for generating an electromagnetic interaction with thepassive magnetic elements, in particular electrical coil elements,wherein the active drive elements at least partially protrude into thebell-shaped body, and by means of a radial interaction between theactive drive elements and the passive magnetic elements the shaft andtherefore the beam steering unit undergo a defined rotational motionaround the beam axis of rotation.

One embodiment relates, for example, to the fact that the active driveelements are fully recessed into the bell-shaped body.

A further embodiment relates, for example, to the fact that at least onerim of the bearing for mounting the shaft in the support protrudes intothe bell-shaped body.

A further embodiment relates, for example, to the fact that the rim ofthe bearing protruding into the bell-shaped body is designed as a rollerbearing rim and roller bodies of the roller bearing rim protrude atleast partially into the bell-shaped body.

A further embodiment relates, for example, to the fact that at least onerim of the bearing for mounting the shaft in the support protrudes intothe beam steering unit, in particular wherein the rim protruding intothe beam steering unit is designed as a roller bearing rim and rollerbodies of the roller bearing rim protrude at least partially into thebeam steering unit.

A further embodiment relates, for example, to the fact that the shaftcomprises only a single effective stabilization region axially along thebeam axis of rotation, which is used to stabilize the shaft against atilting of the shaft relative to the support, wherein the beam steeringunit, the bell-shaped element and the shaft are designed and arrangedwith respect to each other in such a way that their common center ofgravity axially along the beam axis of rotation is located in thestabilization region, in particular wherein the stabilization isachieved exclusively by a bearing which substantiallyaxially-symmetrically surrounds the center of gravity for mounting theshaft in the support.

A further embodiment relates, for example, to the fact that a codingelement for the angle encoder is arranged on the back of the bell-shapedelement, in particular wherein the coding element is designed integrallywith the bell-shaped element.

A further embodiment relates, for example, to the fact that at least oneof the following connections is made exclusively by means of an adhesivebonding and/or compression: a connection of the shaft to thestabilization element, a connection of the shaft to the bell-shapedelement, a connection of the passive magnetic element to the bell-shapedelement, and a connection of the coding element to the bell-shapedelement.

A further aspect of some embodiments of the invention, taken eitheralone or in combination with the previously mentioned embodiments of theinvention, relates to a laser scanner for optical measurement of anenvironment, comprising an optical distance measuring device fordetecting distance measurement data, having a transmitter unit foremitting a distance measurement radiation and a receiver unit forreceiving returning parts of the distance measurement radiation, asupport, a beam steering unit for the distance measurement radiation,which is fixed to the support such that it can rotate around a beam axisof rotation, in particular a fast axis of rotation, and an angle encoderfor recording angle data with respect to a rotation of the beam steeringunit about the beam axis of rotation.

The aspect of some embodiments of the invention is characterized in thatthe beam steering unit is axially mounted in the support along the beamaxis of rotation via a shaft, wherein the beam steering unit comprises amirrored surface for a deflection of the distance measurement radiation,in particular a plane mirrored surface which is tilted by 45° withrespect to the beam axis of rotation, or a tilted parabolic mirroredsurface, the shaft has a penetration region at one end, the beamsteering unit has an enclosure region for enclosing the penetrationregion of the shaft during a coupling of the beam steering unit to theshaft, the enclosure region has a shape which is suitable for enclosingthe shaft over a length of the penetration region during the coupling insuch a way that in the coupled condition a gap with a defined widthexists between the shaft and the enclosure region of the beam steeringunit, the enclosure region comprises a stabilization element that can bepressed in the gap for tolerance compensation and for the stableconnection of the beam steering unit to the shaft, in an uncoupledcondition the stabilization element has a thickness which is greaterthan the width of the gap, and the beam steering unit, in particular theenclosure region, the shaft and the stabilization element are designedin such a way and interact in such a way that during the coupling of thebeam steering unit to the shaft the stabilization element arrangedbetween the enclosure region and the shaft is pressed into the gap, andin the coupled condition is present in the gap in such a deformed state,in particular wherein at least a portion of the stabilization element isplastically deformed, that defined residual elastic forces radially tothe beam axis of rotation act on the beam steering unit and the shaft,that the beam steering unit and the shaft are stabilized in relation toeach other in the axial direction with respect to the beam axis ofrotation, the beam steering unit is stabilized against a tiltingrelative to the shaft over a stabilization region defined by the lengthof the penetration region, and the residual elastic forces do not act onthe mirrored surface, apart from a defined tolerance range.

For example, one embodiment relates to the fact that the stabilizationelement and the shaft are adhesively bonded to each other during thecoupling.

A further embodiment relates, for example, to the fact that theenclosure region comprises at least two stabilization elements spacedapart in the axial direction with respect to the beam axis of rotation.

A further embodiment relates, for example, to the fact that thestabilization element is annular.

A further embodiment relates, for example, to the fact that thestabilization element is made of a material with homogeneous plasticproperties, in particular with a homogeneous plastic flow region.

A further embodiment relates, for example, to the fact that thestabilizing element is integrated into the beam steering unit, inparticular wherein the stabilization element is injection molded ontothe beam steering unit or the beam steering unit and the stabilizationelement are integrally designed.

A further embodiment relates, for example, to the fact that the definedtolerance range for an effect of the residual elastic forces on themirrored surface is selected in such a way that a surface accuracy ofthe mirrored surface of plus/minus 5 μm, in particular of plus/minus 3μm, in particular of plus/minus 1 μm or of plus/minus 300 nm withrespect to a defined ideal design for the mirrored surface isguaranteed.

A further aspect of some embodiments of the invention, taken eitheralone or in combination with the previously mentioned embodiments of theinvention, relates to a laser scanner for optical measurement of anenvironment, comprising an optical distance measuring device fordetecting distance measurement data, having a transmitter unit foremitting a distance measurement radiation and a receiver unit forreceiving parts of the distance measurement radiation returning from theenvironment, a support, a beam steering unit for the distancemeasurement radiation, which is fixed to the support such that it canrotate around a beam axis of rotation, in particular a fast axis ofrotation, wherein the beam steering unit comprises a mirrored surfacefor a deflection of the distance measurement radiation, in particular aplane mirrored surface which is tilted with respect to the beam axis ofrotation, or a parabolic mirrored surface, and an angle encoder fordetecting angle data with respect to a rotation of the beam steeringunit about the beam axis of rotation, wherein the distance measurementdata and the angle data, hereafter designated as measurement data, aredetected during a measurement process which comprises a scanning sensingby means of the distance measuring device with a defined progressive, inparticular continuous, rotation of the beam steering unit about the beamaxis of rotation, and with a continuous emission of the distancemeasurement radiation and a continuous reception of returning parts ofthe distance measurement radiation.

The aspect of some embodiments of the invention is characterized in thata receiving optics for parts of the distance measurement radiationreturning via the mirrored surface is arranged on the support, inparticular wherein the optical axis of the receiving optics is aligned,specifically coaxially, with respect to the beam axis of rotation, anoutlet area for the emission of the distance measurement radiation inthe direction of the mirrored surface is arranged on the support and theoutlet area has a lateral offset with respect to the optical axis of thereceiving optics and the distance measurement radiation emitted by theoutlet area is emitted onto the mirrored surface parallel to the opticalaxis of the receiving optics.

One embodiment relates, for example, to the fact that the receivingoptics has a cutout or window, in particular a plane glass window, intowhich the outlet area is placed, or which forms the outlet area.

A further embodiment relates, for example, to the fact that the outletarea is arranged next to the receiving optics, in particular immediatelyadjoining the receiving optics.

A further embodiment relates, for example, to the fact that the outletarea is designed in such a way that, due to the geometry and orientationof the outlet area, the maximum beam diameter at the outlet area of theoutgoing distance measurement radiation is substantially enclosed by theoutlet area, in particular wherein the geometry and orientation of theoutlet area substantially corresponds to the geometry and orientation ofthe beam waist (the beam cross-section) of the outgoing distancemeasurement radiation at the outlet area.

A further embodiment relates, for example, to the fact that thetransmitter unit comprises a laser diode for generating the distancemeasurement radiation as laser radiation and the beam cross-section ofthe outgoing distance measurement radiation at the level of the outletarea has an oval shape, in particular an elliptical shape, in particularwith a short semi-axis oriented in the direction of the lateral offset.

A further embodiment relates, for example, to the fact that thereceiving optics also comprises a corrective optics to allow for aparallax effect caused by the lateral offset of the outlet area relativeto the beam axis of rotation for parts of the distance measurementradiation returning from a distance which is shorter than a definednear-field distance, in particular wherein the corrective optics isimplemented as a cylindrical lens.

A further embodiment relates, for example, to the fact that acompensation algorithm is provided in order to compensate forcompensation parameters dependent on the angle data for a parallaxeffect with respect to outgoing and returning parts of the distancemeasurement radiation, during the continuous rotation of the beamsteering unit about the beam axis of rotation and induced by the lateraloffset of the outlet area with respect to the beam axis of rotation, inparticular wherein the compensation parameters are taken into account aspart of a referencing of the measurement data with respect to a commoncoordinate system.

A further embodiment relates, for example, to the fact that the outletarea and the compensation algorithm are designed in such a way thatwithin a defined measurement tolerance for referencing the measurementdata with respect to the common coordinate system, no further adjustmentof the laser scanner is required in addition to the compensationalgorithm for the compensation of the parallax effect.

A further embodiment relates, for example, to the fact that the outletarea and the receiving optics are arranged in such a way that a lateraloffset of at least 0.5 cm exists between a virtual extension of theoptical axis of the receiving optics and a central propagation axis ofthe distance measurement radiation at the height at which the distancemeasurement radiation impinges on the beam steering unit.

A further embodiment relates, for example, to the fact that thetransmitter unit and the receiver unit are arranged on a common printedcircuit board.

A further aspect of some embodiments of the invention, taken alone or incombination with the above-mentioned aspects of the invention, relatesto an electronic laser distance measurement module for a distancemeasurement to a target object, in particular for use in a laserscanner, wherein the laser distance measurement module comprises atransmitter unit for generating transmission signals, in particularwherein the transmission signals are generated by pulsed laserradiation, a receiver unit for receiving parts of the transmissionsignals returning from the target object as received signals, a receivercircuit for conditioning and digitization of the received signals, sothat a distance to the target object is ultimately derivable based onthe signal propagation time method, and a controller for the transmitterunit and the receiver circuit.

The aspect of some embodiments of the invention is characterized in thatthe receiver circuit comprises a comparator stage for deriving a signalamplitude of a received signal, an amplifier stage for adjusting asignal amplitude, in particular by amplification or attenuation of aninput signal, a first and a second analog-to-digital conversion stage,wherein the receiver circuit as well as the transmitter unit can becontrolled by the controller in such a way that a continuous sequence ofdistance measurements under alternating use of the first and secondanalog-to-digital conversion stage comprises first distance measurementby means of the first analog-to-digital conversion stage, in particularbased on a first signal packet of successive received signals, inparticular based on a first signal packet of successive receive signals,second distance measurement by means of the second analog-to-digitalconversion stage, in particular based on a second signal packet ofsuccessive received signals, use of a first reception signal as a testsignal, use of a second reception signal as a measurement signal,feeding the test signal to the comparator stage and derivation of asignal amplitude of the test signal by the comparator stage, adjustingthe amplifier stage for at least parts of the reception signalscontaining the measurement signal based on the derived signal amplitudeof the test signal, so that at least the measurement signal is presentas an input signal in the control range of the first and/or secondanalog-to-digital conversion stage downstream of the amplifier unit.

One embodiment relates, for example, to the fact that the receivercircuit also comprises an activation unit, by means of which a firstadjustment is carried out, wherein the test signal is taken into accountfor the derivation of the distance to the target object, and a secondadjustment is carried out, wherein the test signal is discarded for thederivation of the distance to the target object, in particular wherein arange of values for a usable signal amplitude of the test signal isdefined, the signal amplitude of the sample signal derived by thecomparator stage is compared with the range of values, and theactivation unit is controlled based on the comparison of the signalamplitude with the range of values, that if the signal amplitude of thetest signal is within the range of values, the test signal is taken intoaccount for the derivation of the distance to the target object, and ifthe signal amplitude of the test signal is outside the value range, thetest signal is discarded for the derivation of the distance to thetarget object.

A further embodiment relates, for example, to the fact that theadjustment of the amplifier unit and the derivation of the distance tothe target object as part of a single distance measurement is based on asignal packet consisting of a maximum of three consecutive receivedsignals.

A further embodiment relates, for example, to the fact that a receivedsignal of an immediately preceding distance measurement from theplurality of distance measurements is used as a current test signal fora current distance measurement from the plurality of distancemeasurements, in particular wherein the most recently received signal ofthe immediately preceding distance measurement is used as the currenttest signal.

A further aspect of some embodiments of the invention, taken alone or incombination with the above-mentioned embodiments of the invention,relates to an electronic laser distance measurement module for adistance measurement to a target object, in particular for use in alaser scanner, wherein the laser distance measurement module comprises atransmitter unit for generating transmission signals, in particularwherein the transmission signals are generated by pulsed laserradiation, a receiver unit for receiving parts of the transmissionsignals returning from the target object as received signals, a receivercircuit for conditioning and digitization of the received signals, sothat a distance to the target object is ultimately derivable based onthe signal transit time method, and a controller for the transmitterunit and the receiver circuit.

The aspect of some embodiments of the invention is characterized in thatthe receiver circuit comprises a plurality, including at least a firstand a second, of analog-to-digital conversion stages, wherein thecontroller is configured for controlling the receiver circuit and thetransmitter unit in such a way that a continuous sequence of distancemeasurements comprises an alternating use of the plurality ofanalog-to-digital conversion stages, staggered one after the other andin alternate sequence, for one distance measurement each, wherein eachanalog-to-digital conversion stage of the plurality of analog-to-digitalconversion stages has one closed sampling phase per distance measurementfor sampling an incoming signal, in particular a pulse packet, andthereafter a closed output phase for outputting values sampled duringthe sampling phase, wherein during the alternating usage, the respectiveoutput phases of the first analog-to-digital conversion stage aretemporally located in the respective sampling phases of the secondanalog-to-digital conversion stage, and the respective output phases ofthe second analog-to-digital conversion stage are temporally located inthe respective sampling phases of the first or another of the pluralityof analog-to-digital conversion stages.

A further aspect of some embodiments of the invention, taken eitheralone or in combination with the previously mentioned aspects of theinvention, relates to a laser scanner for optical measurement of anenvironment, comprising an optical distance measuring device fordetecting distance measurement data, having one of the above describeddistance measurement modules, a support, a beam steering unit for thedistance measurement radiation, which is fixed to the support such thatit can rotate about a beam axis of rotation, in particular a fast axisof rotation, and an angle encoder for detecting angle data with respectto a rotation of the beam steering unit about the beam axis of rotation,wherein the distance measurement data and the angle data, hereafterdesignated as measurement data, are detected during a measurementprocess which comprises a scanning sensing by means of the distancemeasuring device with a defined progressive, in particular continuous,rotation of the beam steering unit about the beam axis of rotation, andwith a continuous emission of the distance measurement radiation and acontinuous reception of returning parts of the distance measurementradiation.

A further aspect of some embodiments of the invention, taken separatelyor in combination with the other embodiments of the invention, relatesto a laser scanner for optical measurement of an environment, comprisingan optical distance measuring device for the detection of distancemeasurement data, with a transmitter unit for emitting a distancemeasurement radiation and a receiver unit for receiving returning partsof the distance measurement radiation, a base, a support which is fixedto the base such that it can rotate about a support axis of rotation, inparticular a slow axis of rotation, a beam steering unit for thedistance measurement radiation which is fixed to the support such thatit can rotate about a beam axis of rotation, in particular a fast axisof rotation, substantially orthogonal to the support axis of rotation, afirst angle encoder for detecting data relating to a first rotation ofthe support about the support axis of rotation and a second angleencoder for detecting data relating to a rotation of the beam steeringunit about the beam axis of rotation, wherein the distance measurementdata and the first and second angle data, hereafter referred to asmeasurement data, are detected as part of a measurement process whichcomprises a scanning sensing by means of the distance measuring devicewith a defined progressive, in particular continuous, rotation of thesupport about the support axis of rotation, with a defined progressive,in particular continuous, rotation of the beam steering unit about thebeam axis of rotation, and with a continuous emission of the distancemeasurement radiation and a continuous reception of returning parts ofthe distance measurement radiation.

The aspect of some embodiments of the invention is characterized in thatthe support has a skeletal structure consisting of at least twoseparately detachable support structures as the skeletal parts, a firstof the two support structures is rotatably mounted with respect to thebase, a second support structure is coupled only to the first supportstructure, in particular based on a connection using normal pins, thefirst support structure has a superstructure extending in the directionof the support axis of rotation, by means of which a stable mounting ofthe second support structure with respect to a tilting of the secondsupport structure relative to the support axis of rotation can beachieved, and the beam steering unit is mounted exclusively within thesecond support structure such that it can rotate with respect thereto.

One embodiment relates, for example, to the fact that the first supportstructure is based on an inverted T-shape, namely wherein a circulardisk connected to the base or an annular disk connected to the baseforms the T-crossbar, and the superstructure forms the T-vertical.

A further embodiment relates, for example, to the fact that the supporthas a third support structure as a further skeletal part, which isseparately detachably fixed to the superstructure of the first supportstructure, the second and third support structure are each substantiallybased on a plate structure with one flat side, and the superstructurewith two opposite contact sides pointing away from each other forms aholder, on the one hand for the flat side of the second supportstructure and, on the other hand, for the flat side of the third supportstructure.

A further embodiment relates, for example, to the fact that the laserscanner comprises a surface sensor for detecting surface sensor data, inparticular, at least one color camera for recording image data, whereinthe sensor defines an optical axis of the sensor and a viewing directionof the sensor along the optical axis, the distance measuring device isarranged in the second support structure, the surface sensor is arrangedin the third support structure, and that the distance measuring deviceand/or the surface sensor is interchangeable in a modular fashion, inparticular wherein the first or second or third or another supportstructure comprises a power supply unit for the distance measuringdevice and/or the surface sensor.

A further aspect of some embodiments of the invention, taken separatelyor in combination with the previously mentioned embodiments of theinvention, relates to a laser scanner for optical measurement of anenvironment, comprising an optical distance measuring device for thedetection of distance measurement data, with a transmitter unit foremitting a distance measurement radiation and a receiver unit forreceiving returning parts of the distance measurement radiation, a base,a support which is fixed to the base such that it can rotate about asupport axis of rotation, in particular a slow axis of rotation, a beamsteering unit for the distance measurement radiation, which is fixed tothe support such that it can rotate about a beam axis of rotation, inparticular a fast axis of rotation substantially orthogonal to thesupport axis of rotation, a first angle encoder for detecting datarelating to a first rotation of the support about the support axis ofrotation and a second angle encoder for detecting data relating to arotation of the beam steering unit about the beam axis of rotation,wherein the distance measurement data and the first and second angledata, hereafter referred to as measurement data, are detected as part ofa measurement process which comprises a scanning sensing by means of thedistance measuring device with a defined progressive, in particularcontinuous, rotation of the support about the support axis of rotation,with a defined progressive, in particular continuous, rotation of thebeam steering unit about the beam axis of rotation, and with acontinuous emission of the distance measurement radiation and acontinuous reception of returning parts of the distance measurementradiation.

The aspect of some embodiments of the invention is characterized in thatthe laser scanner comprises a status indicator for an indication of adevice status, in particular for indicating a status of the measurementprocess, the status indicator is arranged on the support, which means itco-rotates when the support rotates about the support axis of rotation,that the status display is designed in such a way that it appearssubstantially identical around its circumference with respect to thesupport axis of rotation in all azimuthal directions, so thatirrespective of a rotational position of the support about the supportaxis of rotation, for a user of the laser scanner the same informationprovided by the status indicator is visible and readable from allhorizontal user perspectives.

One embodiment relates for example to the fact that the status displayis formed by means of individual lamps, which are arranged—in particulardirectly—adjacent with a substantially identical elevation over the fullextent of the support.

A further embodiment relates, for example, to the fact that the statusindicator is implemented by means of continuous and interruption-freelighting means, which substantially completely surround the support andthe support axis of rotation, in particular wherein the lighting meansare implemented as an LED ring.

A further embodiment relates, for example, to the fact that the statusindicator is designed by means of a fiber-optic ring with at least onecoupling input for light, in particular by means of two or four couplinginputs, wherein with increasing distance from the coupling inputposition along the fiber-optic ring the ratio of radiation, namely theradial light extraction, to transmission of the light along thefiber-optic ring increases.

A further embodiment relates, for example, to the fact that the statusindicator is designed in such a way that the device status is disclosedto a user by means of a visual coding, in particular by means of adefined color coding of the status indicator and/or by means of adefined flash coding of the status indicator.

A further aspect of some embodiments of the invention, taken eitheralone or in combination with the previously mentioned aspects of theinvention, relates to a laser scanner for optical measurement of anenvironment, comprising an optical distance measuring device fordetecting distance measurement data, having a transmitter unit foremitting a distance measurement radiation and a receiver unit forreceiving returning parts of the distance measurement radiation, asurface sensor for detecting surface sensor data, in particular, atleast one color camera for recording image data, wherein the sensordefines an optical axis of the sensor and a viewing direction of thesensor along the optical axis, a support, a beam steering unit for thedistance measurement radiation, which is fixed to the support such thatit can rotate around a beam axis of rotation, in particular a fast axisof rotation, and an angle encoder for recording angle data with respectto a rotation of the beam steering unit about the beam axis of rotation.

The aspect of some embodiments of the invention is characterized in thatthe support is implemented by means of a skeletal structure, the supportcomprises a cover carried by the skeletal structure and detachabletherefrom as a shell element, and the surface sensor is secured to theshell element and carried by the shell element.

One embodiment relates, for example, to the fact that the laser scannercomprises a multiplicity of surface sensors, each of which is separatelymounted on the shell element and carried separately by the shellelement, in the sense that each surface sensor of the multiplicity ofsurface sensors is carried separately and in each individual case by theshell element, in particular wherein the shell element is formed withaperture openings for the surface sensors, the individual surfacesensors of the multiplicity of surface sensors are secured to the insideof the shell element and the individual surface sensors of themultiplicity of surface sensors in each case look through one of theaperture openings of the shell element.

A further aspect of some embodiments of the invention, taken separatelyor in combination with the previously mentioned embodiments of theinvention, relates to a laser scanner for optical measurement of anenvironment, comprising an optical distance measuring device for thedetection of distance measurement data, with a transmitter unit foremitting a distance measurement radiation and a receiver unit forreceiving returning parts of the distance measurement radiation, a base,a support which is fixed to the base such that it can rotate about asupport axis of rotation, in particular a slow axis of rotation, a beamsteering unit for the distance measurement radiation which is fixed tothe support such that it can rotate about a beam axis of rotation, inparticular a fast axis of rotation, substantially orthogonal to thesupport axis of rotation, a first angle encoder for detecting datarelating to a first rotation of the support about the support axis ofrotation and a second angle encoder for detecting data relating to arotation of the beam steering unit about the beam axis of rotation,wherein the distance measurement data and the first and second angledata, hereafter referred to as measurement data, are detected as part ofa measurement process which comprises a scanning sensing by means of thedistance measuring device with a defined progressive, in particularcontinuous, rotation of the support about the support axis of rotation,with a defined progressive, in particular continuous, rotation of thebeam steering unit about the beam axis of rotation, and with acontinuous emission of the distance measurement radiation and acontinuous reception of returning parts of the distance measurementradiation.

The aspect of some embodiments of the invention is characterized in thatthe distance measuring device is designed in such a way that ameasurement beam ensemble, formed from a multiplicity of individualdistance measurement beams is emitted, in particular wherein themeasurement beam ensemble is deflected during the measurement processvia a mirrored surface of the beam steering unit common to themultiplicity of distance measurement beams.

One embodiment relates for example to the fact that the maximumdivergence between adjacent individual beams of the measurement beamensemble is less than 15 degrees, in particular less than 1 degree.

A further embodiment relates for example to the fact that the individualbeams of the measurement beam ensemble are emitted from the support inthe direction of the beam steering unit as a beam fan, forming asingle-beam line, in particular wherein the single-beam line extendsalong a perpendicular to the beam axis of rotation and perpendicular tothe support axis of rotation, in particular wherein the beam fanconsists of a maximum of ten individual beams.

A further aspect of some embodiments of the invention, taken eitheralone or in combination with the previously mentioned embodiments of theinvention, relates to a laser scanner for optical measurement of anenvironment, comprising an optical distance measuring device fordetecting distance measurement data, having a transmitter unit foremitting a distance measurement radiation and a receiver unit forreceiving returning parts of the distance measurement radiation, asupport, a beam steering unit for the distance measurement radiation,which is fixed to the support such that it can rotate around a beam axisof rotation, in particular a fast axis of rotation, and an angle encoderfor detecting angle data with respect to a rotation of the beam steeringunit about the beam axis of rotation, wherein the measurement datacomprise the distance measurement data and the angle data that aredetected during a measurement process which comprises a scanningsampling by means of the distance measuring device with a definedprogressive, in particular continuous, rotation of the beam steeringunit about the beam axis of rotation, and with a continuous emission ofthe distance measurement radiation and a continuous reception ofreturning parts of the distance measurement radiation.

The aspect of some embodiments of the invention is characterized by areceiving element for receiving the base, wherein the receiving elementcan be detached from the base by means of a latching device, and whereinthe locking device comprises a cutout portion on the base into which aring is recessed, said ring having a circumferentially continuous cavityin its interior, and comprises a spigot on the receiving element,wherein the spigot comprises at least three latching bodies, wherein ina basic position of a release device the latching bodies push radiallyoutwards in order to block the ability to detach the receiving elementfrom the base by the fact that the latching bodies engage in the cavity,and the activation of the release device enables the latching bodies toradially escape into the spigot in order to allow the ability of thereceiving element to detach from the base.

One embodiment relates for example to the fact that the cutout portionis designed to be cylindrical.

A further embodiment relates, for example, to the fact that thereceiving element is a tripod head or is designed for attachment to atripod head.

A further embodiment relates, for example, to the fact that a latchingis designed as a rotation body, in particular as a sphere or anellipsoid, a trapezoid, a pyramid, a trapezoid having rounded corners,or a pyramid having rounded corners.

A further embodiment relates for example to the fact that the latchingbodies and the cavity are designed and matched to each other in such amanner that the engagement of the latching body in the cavity causes aself-centering of the base to occur, in particular a self-centering withrespect to the support axis of rotation.

A further embodiment relates, for example, to the fact that the releasedevice is arranged in the spigot and has at least one radial pin foractivating the release device, an axial pin for blocking or allowing thedetachment facility, and a tensioning spring to maintain the basicposition, wherein the radial pin, the axial pin and the tensioningspring are operatively connected in such a way that in the initial stateof the release device the axial pin forces the latching bodies radiallyoutwards, and on activating the release device a displacement of theradial pin moves the axial pin towards the tensioning spring, and theaxial pin releases space due to its displacement and therefore enablesthe radial escape of the latching bodies into the spigot.

A further embodiment relates, for example, to the fact that in the basicposition, the axial pin presses the latching bodies into the cavity ofthe ring by means of a tensioning force due to the tensioning spring.

A further embodiment relates, for example, to the fact that eachlatching body has at least two points of contact with the cavity, inparticular, at least one contact line with the cavity.

A further aspect of some embodiments the invention, in combination withthe previously mentioned embodiments of the invention, relates to alaser scanner wherein an axial position calibration procedure isprovided for deriving axial position calibration parameters, which aretaken into account during a referencing of the measurement data in acommon coordinate system, in particular wherein the axial positioncalibration procedure comprises measurement of an already knownenvironment and/or known objects in the environment to be measured, inparticular wherein for the axial position calibration procedure thelaser scanner is arranged in a hollow test body with known spatialdimensions, and/or in a test environment and/or in the environmentprovided as part of the actual measurement process, a set of testobjects with known positioning relative to each other and/ordimensioning are installed and measured as part of the axial positioncalibration process.

A further aspect of some embodiments of the invention, in combinationwith the previously mentioned embodiments of the invention, relates to alaser scanner, wherein during the measurement process the beam steeringunit rotates about the beam axis of rotation with a rotation speed of atleast 50 Hz, in particular of at least 100 Hz, specifically of at least250 Hz, and/or during the measurement process the base rotates about thesupport axis of rotation with a rotation speed of at least 0.01 Hz, inparticular of at least 0.02 Hz, specifically of at least 0.03 Hz.

A further aspect of some embodiments of the invention, in combinationwith the previously mentioned embodiments, relates to a laser scanner,wherein during the measurement process, based on the rotation speed ofthe beam steering unit about the beam axis of rotation and based on apulse frequency of the distance measurement radiation, a minimumsampling point density of at least 3 points per 1° angle of rotation isset.

BRIEF DESCRIPTION OF THE DRAWINGS

The system according to the invention and the laser scanner according tothe invention are described in detail in the following in a purelyexemplary way by reference to exemplary embodiments shown schematicallyin the drawings. Identical elements are labelled with the same referencenumerals in the figures. The described embodiments are generally notshown true to scale and they are also not to be interpreted as limitingthe invention.

Individually, they show:

FIG. 1 : a typical laser scanner according to the prior art formeasuring a room;

FIG. 2 : typical equipment components for scanning using a commonlyavailable laser scanner;

FIG. 3 : a system according to the invention for optical measurementwith a laser scanner and a (wireless) monitoring, processing and displayunit;

FIG. 4 : a further embodiment of a system according to the invention foroptical measurement with a laser scanner and a (wireless) monitoring,processing and display unit;

FIG. 5 : a camera arrangement according to the invention of a pluralityof cameras integrated in the laser scanner with respect to a centralreference point;

FIG. 6 : a camera arrangement according to the invention with specificillumination means for individual camera viewing directions;

FIG. 7 : a use according to the invention of the same rotating beamsteering unit for the transmitted radiation and the received radiationby means of a biaxial arrangement of the beam outlet with respect to theoptical axis of the lens unit;

FIG. 8 : a further use according to the invention of the same rotatingbeam steering unit for the transmitted radiation and the receivedradiation by means of a window integrated in the lens unit for thetransmitted beam;

FIG. 9 : a lens unit according to the invention with a window integratedin the lens unit for the transmitted beam and with a corrective opticsfor measurement in the near range;

FIG. 10 : a receiver circuit according to the invention with acomparator stage and two analog-to-digital conversion stages foradjusting a signal amplitude of a measuring signal and an increase inthe measurement rate;

FIG. 11 : example illustration of pulse packets and test and measurementsignals as part of a receiver circuit according to the invention withtwo analog-to-digital conversion stages;

FIG. 12 : an arrangement according to the invention of a laser scannerwith a passive base with regard to scanning and data acquisition, with ashort vertical axis and an integration of the motor in the support forthe rotation of the support;

FIG. 13 a,b : integration according to the invention of the motor forthe rotation of the support in the support, and mounting according tothe invention based on a short vertical axis by means of a four-pointrolling bearing (a) or a sliding bearing (b);

FIG. 14 a,b : a mounting according to the invention and a compact driveaccording to the invention of the beam steering unit about the fast axisby means of a bell element;

FIG. 15 : a further embodiment according to the invention of the bellelement with an encoder disc for an angle encoder integrated in the bellelement;

FIG. 16 a,b : a coupling according to the invention of a beam steeringunit to a shaft along the beam axis of rotation by means of compressiblestabilization elements;

FIG. 17 a,b : an arrangement according to the invention of a laserscanner by means of a skeletal, three-part support;

FIG. 18 : a typical use of a reference element in the support of a laserscanner;

FIGS. 19 a and 19 b : a multi-beam arrangement according to theinvention of a laser scanner;

FIGS. 20 a and 20 b : a laser scanner with a receiving element (quickrelease) according to the invention, for example, for securing the laserscanner on a tripod.

DETAILED DESCRIPTION

FIG. 1 shows a typical laser scanner 1 according to the prior art, herewith two rotational axes, for example mounted on a tripod 2, wherein thelaser scanner 1 comprises a slow (vertical) axis of rotation—alsoreferred to as the support axis of rotation 3—for an azimuthal rotationof the laser scanner 1, or a rotation of a support 4 of the laserscanner about a base 5 of the laser scanner 1, and a fast (horizontal)axis of rotation—also referred to as the beam axis of rotation 6—withrespect to a fast rotating beam deflection element 7, mounted in thesupport 4 of the laser scanner 1.

For a sensing of linear or linearly movable structures and environments,such as, for example, railway track systems, roads, tunnels systems orair fields, a base or azimuth rotational axis is often dispensed withand instead, the laser scanner is mounted on a means of locomotion, suchas a land-based or airborne carrier vehicle. Such laser scanners withjust one beam axis of rotation 6 are also called profilers.

In particular profilers, but also two-axis laser scanners for acontiguous measurement of a large area, often also have a position andorientation system, which is, for example, directly integrated in thelaser scanner to automatically reference local sensing data with aglobal 3D coordinate system.

The laser scanner 1 here also has a camera 8, for example, for recordingRGB data, wherein the camera images of the environment can be associatedwith the sensing data generated by means of the rotating distancemeasurement beam 9 and associated angle encoder data for the directionof the distance measurement beam 9. The camera can in particular beindividually movable, in order, for example, to record different fieldsof view and/or to orient the camera images and the scanning data withrespect to a common reference surface or a common coordinate system.

FIG. 2 shows typical principal components of a common laser scanner 1′,here for example with two axes of rotation, wherein the laser scanner 1′is based on a design using a base 5 and a support 4, wherein the support5 is rotatably mounted 13 on the base 5 about a support axis of rotation3, in particular a slow rotation axis. Often, the rotation of thesupport 4 about the support axis of rotation 3 is also called azimuthalrotation, regardless of whether the laser scanner 1′, or the supportaxis of rotation 3, is exactly vertically aligned.

The core component of the laser scanner 1′ is formed by an opticaldistance measuring device 10 arranged in the support 4 for recordingdistance measurement data, with a transmitter unit for emitting adistance measurement radiation 9, for example pulsed laser radiation,and a receiver unit with a receiver optics, in particular a lens 11, anda light-sensitive sensor for receiving returning parts of the distancemeasurement radiation 9, wherein an echo is received from aback-scattering surface point of the environment and, for example, basedon the propagation time, the shape and/or the phase of the pulse, adistance to the surface point is derived.

A scanning of the environment is carried out by a variation of theorientation of the emission direction of the distance measurement beam 9by means of a rotating beam steering unit 7 for the distance measurementradiation, which is mounted 13 in the support 4 such that it can rotateabout a beam axis of rotation 6, in particular a fast rotation axis,substantially orthogonal to the support axis of rotation 3. Using angleencoders 12 for detecting angle data, for example fixed angle angularpositions and/or relative angular changes with respect to a rotation ofthe support 4 about the support axis of rotation 3 and angle data withrespect to a rotation of the beam steering unit 7 about the beam axis ofrotation 6, the emission direction of the distance measurement beam 9 isdetected and associated with correspondingly acquired distancemeasurement data. By using a plurality of such measurement pointsessentially the entire environment can therefore be spatially measured,wherein, for example, a desired point-to-point resolution is set byadjusting the pulse rate of the distance measurement beam 9 and/or byadjusting the rotational speed of the beam steering unit 7. A subsequentdisplay of the data can be based, for example, on common data processingsteps and/or display methods, for example, for displaying the acquireddata in the form of a 3D point cloud.

The beam steering unit 7 has a mirrored surface 14 for a deflection ofthe distance measurement radiation 9, in particular, a mirrored surfacewhich is tilted with respect to the beam axis of rotation 6, such as aplane or parabolic mirrored surface, which on account of the fastrotation of the beam steering unit 7 and the resulting large centrifugalforces is typically designed to be integral with the rotating body ofthe beam steering unit 7, or less commonly by attaching a separateoptical component such as a separate mirror.

A defined scanning motion of the distance measurement beam 9 with aminimal tolerance for the guidance of the distance measurement beam 9with a high angular accuracy typically requires a mounting 13 of thesupport 4 and the beam steering unit 7 with the minimum possible amountof play, that is to say, with a minimum tolerance for a tilting of thesupport 4 with respect to the support axis of rotation 3, respectivelyfor a tilting of the beam steering unit 7 with respect to the beam axisof rotation 6. In addition, the mirrored surface 14 typically has a highsurface accuracy to ensure, for example, an optimal beam collimation andintensity sensitivity.

To ensure a zero-play mounting 13 with a minimum tilting of the beamsteering unit 7 and the support 4, the mounting 13 is typicallyimplemented in each case along an effective stabilization region 15 witha maximum axial extent. Due to the weight of the support 4, in the priorart the mounting 13 of support 4 about the support axis of rotation 3 istypically based on designing a vertical axis 16 to be as long (or high)as possible relative to the total volume of the support 4, which incombination with the mounting 13 of the support 4 defines astabilization region 15 with a maximum axial extent.

FIG. 3 shows an inventive system 17 for optical measurement and forimaging an environment, here for example in the area of interior roommeasurement, wherein a laser scanner 1″, for example to minimizepossible shadowing and/or dead angles, can be placed anywhere in theroom, here on a table 18 in the room. The system 17 comprises the laserscanner 1″ for detecting measurement data, i.e. distance measurementdata and angle data, provided by a distance measuring unit and angleencoders for determining the emission direction of the distancemeasurement beam. The measurement data also comprise surface sensordata, provided by a sensor arranged on the support 4 and co-rotatingwith the support 4, for example a camera 8, in particular an RGB cameraor an infrared camera.

The measurement data is recorded by the laser scanner 1″ as part of ameasurement process, defined by a scanning sensing using the distancemeasuring device with a defined continuous rotation of the support 4about the support axis of rotation 3, a defined continuous rotation ofthe beam steering unit 7 about the beam axis of rotation 6 and acontinuous emission of the distance measurement radiation and acontinuous reception of returning parts of the distance measurementradiation, as well as a repeated reading of the surface sensor 8 withrespect to different azimuthal viewing directions of the sensor 8.

The inventive system 17 also comprises a processing unit, arranged on aseparate computing device 19 from the laser scanner 1″, in particular acomputer or tablet, for processing parts of the measurement data withrespect to an association of the surface sensor data with the distancemeasurement data and the angle data, wherein the inventive system 17 isdesigned in such a way that already during the data acquisition of themeasurement data as part of the measurement process, at least an initialprocessing of portions of the measurement data is carried out inrelation to an association of the surface sensor data with the distancemeasurement data and the angle data, in particular with the minimumpossible delay, in other words substantially temporally in parallel withthe data recording, and is continuously displayed for a user 20, forexample as a continuously growing colored 3D point cloud, for example bymeans of a display coupled to or integrated with the computing device19. In particular, the laser scanner 1″ and the computing device 19 areconfigured in such a way that the transfer of the measurement data fromthe laser scanner 1″ to the computing device 19, which is carried outsubstantially parallel to the measurement process by means of a datastreaming which is started simultaneously with respect to themeasurement process, for example using a WLAN or Bluetooth connection.In particular, the laser scanner 1″ and the computing device 19 areconfigured in such a way that monitoring and control signals aretransferred from the computing device 19 to the laser scanner 1″ andtherefore the laser scanner 1″ is monitored by the external processingunit 19 and, for example, a defined measurement process of the laserscanner 1″ can be started, stopped, interrupted and/or adjusted from thecomputing device 19.

In laser scanners the scanning by means of the distance measuring deviceis central and in the state of the art, camera data are thereforetypically only recorded after a complete room scan (360 degrees ofazimuth rotation) by the distance measuring device, for example, assupplementary information and often only for selected regions of theenvironment, for example to provide an improved display of a region ofinterest for a user.

Distance measurement modules used in laser scanners for spatialmeasurement typically have no color sensitivity, which means the 3Dpoint cloud generated can be displayed in grayscale levels without theneed to use additional data. As a result of the lack of color effect andthe lack of depth effect supported by the presence of colors, manydetails remain hidden to a human observer. Using RGB data from a colorcamera, for example, a “colored” 3D point cloud can be generated, which,for example, makes its display to the human eye considerably easier.Such a referencing of different data and data sets is nowadays carriedout, for example, using common data processing algorithms in anincreasingly standardized manner.

In the prior art laser scanners are often designed in such a way thatthe field of view of a camera, for example an RGB camera, essentiallyrecords a scanning plane of the distance measurement radiation definedby a virtual 360-degree rotation of the beam steering unit about thebeam axis of rotation, for example by means of parallel alignment of theoptical axis of the camera with respect to the scanning plane or usingappropriate coaxial coupling of the beam path of the camera into thebeam path of the distance measuring device. This has the advantage, forexample, that at least for the viewing range of the camera, directlycorresponding camera and distance measurement data can be recorded. Thisallows, for example, a simultaneous recording of the camera data withthe distance measurement data corresponding to the camera field of view,which can facilitate the referencing of the camera data with thedistance measurement data. Thus, for example, any interference effectsin the environment that occur during the measurement process can then beidentified both in the camera data and in the distance measurement data.

Such an integration and alignment of the camera field of view, however,is often associated with a certain level of integration effort and inparticular in the case of a highly compact construction of the laserscanner is only possible to a limited extent.

One aspect of the invention relates to an integration of the surfacesensor 8, and in particular an RGB camera, in the laser Scanner 1″, sothat the viewing direction of the surface sensor differs significantlyfrom the scanning plane, wherein, for example, a virtual backwardextension of the optical axis of the surface sensor intersects with thescanning plane under a cutting angle of at least degrees, in particularunder an angle of 90 degrees, in particular wherein the scanning planeis not captured by the field of view of the surface sensor.

This arrangement of the camera 8 in the laser scanner allows, forexample, a compact design of the laser scanner 1″ but has thedisadvantage that a simultaneous recording of the camera data withdistance measurement data corresponding to the camera field of view maynot be possible. The inventive arrangement, by contrast, enables aparallel reading of the surface sensor 8, for example the RGB camera,with the scanning with the distance measuring device, which means, forexample, a full-dome measurement can be carried out by the scanningdistance measuring device and the camera 8 in one action, is thusaccelerated, wherein, for example, the distance measurement data, theangle data and the camera data then can be computationally referencedwith respect to one another accordingly.

A complete room scan (360 degrees azimuthal rotation) by means of thedistance measuring device takes a relatively long time compared with a360-degree recording of the camera data. In order nevertheless to ensurea display of the environment started directly with the measurementprocess, in particular as a colored 3D point cloud, one aspect of theinvention relates to the fact that color camera data of the environmentare recorded first, and the scanning by means of the distance measuringdevice is only carried out afterwards. An at least initial processing isthus carried out already based on the relatively quickly recorded cameradata, which are displayed to a user 20, for example as a 2D panoramicview; and an association of the distance measurement data and the angledata with the recorded camera data can be carried out virtually inreal-time with the acquisition of the distance measurement data,allowing a steadily growing colored 3D point cloud to be displayed tothe user 20 substantially in real-time. This allows, for example, arapid assessment of the recorded data by the user 20 and, if necessary,an immediate adjustment or change to the settings of the laser scanner1″, for example, a defined measuring mode with a different pointdensity.

Since the laser scanner 1″ in the context of the system according to theinvention can be controlled by means of an external computer unit 19, inparticular a tablet wirelessly connected to the laser scanner 1″, which,in particular, also performs the computationally intensive associationof the distance measurement data with the camera data and the angle dataas well as the display of the measurement data, the laser scanner 1″ maydesigned to be very compact.

In particular, the laser scanner 1″ itself requires only a minimalnumber of control elements integrated in the laser scanner 1″. Forexample, a laser scanner 1″ according to the invention has only a singleintegrated control element 21, which has an active and an inactivestate, and can be switched by way of an external action in order tooccupy the active or inactive state. The two states, respectively, achange of the state of the control element 21 from the inactive to theactive state, a change of the state of the control element 21 from theactive to the inactive state, a switching of the control element 21 bymeans of a persistent external action during a defined time interval(e.g., continued pressing of a control knob), a coded sequence of statechanges of the control element 21 between the active and inactive stateand/or a coded sequence of temporally continuing external actions on thecontrol element 21 over defined periods of time, are assigned, forexample, individual measurement programs and/or actions of the laserscanner 1″, for example, activation/deactivation of the laser scanner1″, starting a defined measurement process, orinterruption/aborting/restarting a measurement process.

For example, the laser scanner 1″ can also be designed with a positionand orientation system, for example using an inertial system, tiltsensors or a receiver for a global satellite navigation system, which istransferred into an active state by the control element 21, whereuponthe position and/or orientation of the laser scanner 1″ are determinedcontinuously and stored in the measurement data continuously. In thismode, the laser scanner 1″ can then be moved within the room and, forexample, local scanning data can be automatically referenced with aglobal 3D coordinate system.

The laser scanner 1″ may also be designed in such a way that definedmeasurement programs and actions are stored on the laser scanner 1″and/or that new measurement programs and actions, for example, via acorresponding input functionality of the external computing device 19,can be defined and assigned to the states/state changes of the controlelement 21.

A further aspect of the invention relates to a status indicator 22 forindicating a device status, for example, indicating a status of acurrent measurement process, wherein the status indicator 22 is arrangedon the support 4, in other words co-rotates about the support axis ofrotation 3 during the rotation of the support 4. The status indicator 22is then designed in such a way that it appears substantially identicalaround its circumference with respect to the support axis of rotation 3in all azimuthal directions. For example, a user 20 of the laser scanner1″ regardless of their direction of view of the laser scanner 1″ (seenfrom the scanner regardless of an azimuth angular position of the user20) can be provided with the same information, in particular, even whena measurement process is running and the scanner 1″ is rotating.

For example, the status indicator 22 is designed by means of afiber-optic ring with two opposite located coupling inputs for light,wherein with increasing distance from the coupling position along thefiber-optic ring the ratio of radiation emission (radial lightextraction) to transmission of light increases, wherein the devicestatus is revealed to a user 20 by means of a visual coding, forexample, a defined color coding of the status indicator 22 and/or bymeans of a defined flash coding of the status indicator 22.

FIG. 4 shows a further embodiment of an inventive system 17′ for opticalmeasurement and for imaging an environment, for example in the area ofinterior room measurement, wherein the laser scanner 1′ is mounted on atripod. As before (see FIG. 3 ), the laser scanner 1′″ is wirelesslycontrolled via an external computing device 19′, here, for example, bymeans of a tablet, wherein data as well as monitoring and controlsignals are transferred in both directions (laser scanner 1′″ to tablet19′ and vice versa).

In this embodiment the tablet 19′ is also equipped with an inertialmeasurement system and/or tilt sensors, so that the laser scanner 1′″can be controlled on the basis of a location (position, orientation) ofthe computing device 19′, for example substantially synchronously withthe change of position of the computing device 19′.

The tablet 19′ also has a display 23 on which, for example, a currentlive stream from the camera 8 is displayed, so that for differentazimuthal angles of the support 4 of the laser scanner 1′″ a user canobserver the environment from the point of view of the position andorientation of the laser scanner 1′″. This means, for example, it can bechecked prior to the measurement whether the current position of thelaser scanner 1′″ in the room needs to be adjusted in order to avoiddead angles.

The user 20 can also, for example via the tablet 19′, for example usinga touch screen functionality, define different areas of interest 24 inthe environment for various azimuth positions of the laser scanner 1′″,and allocate to these areas of interest 24 settings defined prior to themeasurement process for the recording of measurement data (e.g. cameraresolution, distance measurement accuracy, scanning resolution) and/ordefined settings for the display of parts of the processed measurementdata (e.g. color setting, highlighting).

In addition, the tablet 19′ (or the laser scanner 1′″) can, for example,access data for an augmented reality, so that for example furtherdetails of the surrounding area, hidden to the human eye, are displayedto the user 20 from the point of view of the scanner 1′″, such aselectricity cables or water pipes concealed in the walls, mountingpoints, items of furniture, etc.

FIG. 5 shows a laser scanner according to the invention with a pluralityof cameras 8 integrated on the support, in particular wherein thecameras 8 are arranged in such a way that their optical axes 25 all liein the same azimuthal plane—here, for example, perpendicular to thescanning plane of the distance measurement radiation defined by avirtual 360-degree rotation of the beam steering unit 7 about the beamaxis of rotation 6—and the cameras 8 therefore have the same azimuthalviewing direction.

The laser scanner has a central reference point 26 as the origin for thedistance and angle measurement of the distance measuring device, forexample, the point of intersection of the optical axis of the lens withthe beam steering unit 7. Alternatively, the distance measurement datacan also be corrected by computation with respect to a central referencepoint defined elsewhere.

The cameras 8 are now arranged in accordance with the invention on thesupport 4 in such a way that a virtual backward extension of each oftheir optical axes 25 passes through the central reference point 26, thecameras 8 are thus arranged in a parallax-free manner with respect tothe central reference point 26. This facilitates, for example, thereferencing of the camera data with distance and angle data fordisplaying the measurement data as a 3D point cloud.

In addition, the parallax-free arrangement ensures that the optical axis25 of the camera 8 is always substantially coaxial to an orientation(azimuth and elevation angle) of the distance measurement beam, namely,in the sense that during the measurement process (as part of theazimuthal rotation of the support 4) the camera 8 is sooner or laterrotated into a past or future viewing direction of the distancemeasurement radiation, depending on whether the camera 8 is looking“ahead” or “backwards” with respect to the azimuth direction of rotationand the azimuthally rotating scanning plane of the distance measurementradiation. Due to the parallax-free arrangement the camera 8 thus “sees”the same view as the distance measurement radiation and is subject tosubstantially the same (generated by the environment) shadowing andfield of view blockages as the distance measuring device, and soessentially captures the same sampling points as the distancemeasurement radiation. As a result, for example, corners and edges aredetected substantially identically by the camera 8 and the distancemeasuring device, which, in turn, improves their referencing and/ormodeling based on the camera and scanning data.

In the specific case the cameras 8 can be designed and positioned insuch a way that they cover different elevational fields of view, forexample, three cameras, wherein their visual field cones 27 intersectabove a minimum radius 28 around the central reference point 26.

In particular if the camera with the steepest elevational alignment ofthe optical axis is designed such that its visual field cone 27intersects the support axis of rotation 3, for example, at a distance ofthe above minimum radius 28 from the central reference point 26, thearrangement of the cameras from the minimum radius 28 and greaterenables a full-dome measurement (measurement of the hemisphere definedby the support axis of rotation 3 and the beam axis of rotation 6 acrossthe plane which is defined perpendicular to the support axis of rotation3 and perpendicular to the beam axis of rotation 6).

Also shown in the figure is a camera 29 with parallax with respect tothe central reference point 26, for example, an infrared camera forrecording heat data.

FIG. 6 shows another embodiment of a laser scanner according to theinvention with parallax-free cameras 8 arranged in the support 4 withrespect to a central reference point 26 of the laser scanner as theorigin for the distance and angle measurement of the distance measuringdevice (see FIG. 5 ). The support 4 here additionally has a plurality oflamps 30, each illuminating the field of view of individual cameras,wherein the lamps 30 are designed and arranged in such a way that theyare used for a selectively controllable illumination, substantiallytargeted at the field of view of a specific camera.

The lamps 30 are typically designed in such a way that the divergence oftheir light cone 31 is smaller than the field of view angle of thecameras, wherein each camera is assigned, for example, two or four lamps30 arranged immediately at its side. The lamps 30 are implemented, forexample, as LEDs to emit white light, or in each case as a dual LED,i.e. as LED couplets with two LEDs with distinct emitted spectralranges, in order to achieve color representations of the camera imagesas realistic as possible to the human eye.

In order to achieve an optimal (individual) illumination of theindividual cameras, for example, a 360-degree (azimuth rotation)preliminary scanning can be first carried out using the cameras, forexample with lamps switched off or wherein the lamps are adjusted to auniform intensity in order to derive optimized exposure times andillumination intensities for different azimuth positions for each of theindividual cameras, which are then taken into account in an effectivemeasurement scanning process.

FIG. 7 shows a further embodiment of a laser scanner according to theinvention with a biaxial arrangement with respect to the outgoingdistance measurement beam 9 and the optical axis of the lens 11 or thereceiver of the distance measuring device 10, wherein the outgoingdistance measurement beam 9 and the returning parts 32 of the distancemeasurement beam are deflected into the surroundings via the sameoptical rotating element 7, or into the lens 11 respectively. Thisenables, for example, a compact, simple and robust design of thedistance measuring device 10. In the example shown the outgoing distancemeasurement radiation 9 is arranged in such a way that it exits directlynext to the lens 11 of the receiving unit of the distance measuringdevice 10.

In contrast to the frequently used coaxial arrangement between distancemeasurement beam and lens no central shadowing occurs, caused forexample by a deflection mirror arranged in the center of the lens forthe distance measurement radiation. However, in particular for parts ofthe distance measurement radiation returning from a near field, aparallax effect does occur, caused by the lateral offset of the beamoutlet with respect to the optical axis of the lens. As a result, avertical wall for example is therefore scanned by the distancemeasurement beam with sinusoidal scanning sections instead ofsubstantially vertical scanning sections.

However, on the one hand this effect can be compensated with a suitablecorrective optics in the lens 11, for example a cylindrical lens, and/oron the other hand, compensated computationally using a compensationalgorithm as part of a referencing of the measurement data with respectto a common coordinate system, based on the angular position of the beamsteering unit 7 and the distance detected stored at the time ofrecording the distance measurement radiation.

FIG. 8 shows a further embodiment of a laser scanner according to theinvention with a biaxial arrangement with respect to the outgoingdistance measurement beam 9 and the optical axis of the lens 11 or thereceiver of the distance measuring device 10, wherein here the distancemeasurement radiation 9 exits through an outlet area 33 arranged in thelens 11, for example through a cutout portion or a window in the lens11. This will reduce, on the one hand, the parallax effect caused by thelateral offset between the outgoing distance measurement beam 9 and theoptical axis of the receiver unit and, on the other hand, the effectivelight collection area is better exploited by the beam steering unit 7and the lens 11.

FIG. 9 shows a front view of a lens unit 11 for an inventive biaxialarrangement with respect to the outgoing distance measurement beam 9 andthe optical axis of the lens 11 of the distance measuring device,wherein the distance measurement radiation 9 exits through an outletregion 33 arranged in the lens 11 (see FIG. 8 ), here, for examplearranged directly radially at the edge of the lens 11. In addition, acorrective optics 34 for compensating the parallax effect for parts ofthe distance measurement radiation returning from a near-range of thedistance measurement radiation 9.

The outlet region 33 is typically dimensioned and oriented such that thegeometry of the outlet region 33 substantially only just covers theminimum 35 and the maximum 36 extension of the beam waist of theoutgoing distance measurement radiation 9—for example, depending on thegeometry, arrangement and orientation of a diode generating the distancemeasurement radiation 9, in particular wherein the geometry andorientation of the outlet region are adjusted with regard to thegeometry and orientation of the beam cross section, for example in theform of an oval window.

FIG. 10 shows a schematic drawing of a receiver circuit 37 according tothe invention of a laser distance measuring module according to theinvention, suitable for deriving a distance to a target object based onthe signal propagation-time method, which here is coupled to a pulser38.

For example, the receiver circuit 37 comprises a receiver element 39,such as a receiver diode, a transimpedance amplifier 40 and an amplifierunit 41 for adjusting a signal amplitude, in particular by means ofamplification or attenuation of an input signal, for example by means ofa Variable Gain Amplifier (VGA). The receiver circuit 37 also comprisesa comparator stage 42 for deriving a signal amplitude of a detectedreceived signal, here arranged after the amplifier unit 41, wherein thecomparator stage 42 can also alternatively be arranged in front of theamplifier unit 41. The circuit 37 also has a first 43A and a second 43Banalog-to-digital conversion stage, as well as a control unit 44, forexample a microprocessor or an FPGA (Field Programmable Gate Array).

The comparator stage 42, the amplifier unit 41 and the first 43A andsecond 43B analog-to-digital conversion stage are arranged in such a waythat a continuous sequence of distance measurements comprises a firstdistance measurement by means of the first analog-to-digital conversionstage 43A, for example based on a first signal packet of successivereceived signals, and a second distance measurement by means of thesecond analog-to-digital conversion stage 43B, for example, based on asecond packet of successively received signals. This process involved analternating use of the first 43A and second 43B analog-to-digitalconversion stage, wherein a first received signal is used as a testsignal and a second signal as a measurement signal. The test signal isfed to the comparator stage 42, by means of which a signal amplitude ofthe test signal is derived, wherein an adjustment of the amplifier unit41 is carried out for at least parts of the received signals containingthe measurement signal based on the derived signal amplitude of the testsignal, so that at least the measurement signal is present as an inputsignal in the control range of the analog-to-digital conversion stages43A,B.

In the example shown, the receiver circuit 37 also has an activationunit 45, by means of which, for example, a setting is applied accordingto which the test signal is either additionally taken into account ordiscarded for the derivation of the distance to the target object.Specifically, the activation unit 45 can be configured in such a waythat, for example, with appropriate storage of the detected receivedsignals, a range of values for a usable signal amplitude of the testsignal is defined and the signal amplitude of the sample signal derivedby the comparator stage is compared with the range of values; whereinthe activation unit 45 is controlled based on the comparison of thesignal amplitude with the range of values, so that if the signalamplitude of the test signal is within the range of values, the testsignal is taken into account for the derivation of the distance to thetarget object, and if the signal amplitude of the test signal is outsidethe value range, the test signal is discarded for the derivation of thedistance to the target object.

FIG. 11 shows an example drawing of pulse packets 46 of transmittedsignals 47 and received signals 48 used as test and measurement signalswithin a receiver circuit 37 according to the invention (see FIG. 10 )with two analog-to-digital conversion stages 43A,B (see FIG. 10 ),wherein each analog-to-digital conversion stage has a sampling phase 49for receiving an incoming signal and an output phase 50 for anevaluation of the incoming signal, wherein as part of the alternatinguse of the first 51A and second 51B analog-to-digital conversion stagethe output phase 50 of the first analog-to-digital conversion stagetakes place simultaneously or almost simultaneously with the samplingphase 49 of the second analog-to-digital conversion stage, and theoutput phase 50 of the second analog-to-digital conversion stage takesplace simultaneously or almost simultaneously with the sampling phase 49of the first analog-to-digital conversion stage.

This means that, for example, as part of a single distance measurementby the second analog-to-digital conversion stage, a received signal 52of a received packet of an immediately preceding distance measurementcan be used by the first analog-to-digital conversion stage as thecurrent test signal 53 for the distance measurement of the secondanalog-to-digital conversion stage (and vice versa). As a result, asuitable input signal in the control range of the analog-to-digitalconversion stages can be set after only a few iterations, wherein thealternating use of the analog-to-digital conversion stages allows highdistance measurement rates to be achieved.

FIG. 12 shows a laser scanner according to the invention with a“passive” base 5′ with regard to scanning and data acquisition, herewith a short axial vertical axis 54 compared to the radial extent andwith the motor 55 for the rotation of the support 4 integrated in thesupport 4.

The base 5′ is passive to the extent that all active electronicsrequired for the motorization of the rotation around the support axis ofrotation 3—for example, for a direct drive, piezoelectric drive orfriction-wheel drive—is arranged exclusively in the support 4 andco-rotates with the support 4 about the support axis of rotation 3,wherein, for example, an active drive element 55 for the rotation of thesupport 4 about the support axis of rotation 3, here a rotary motor witha drive shaft 56 coupled to the motor, and a power supply unit for theactive drive element 55 are each arranged entirely in the support 4.

In the example shown, the drive for the rotation of the support 4 aboutthe support axis of rotation 3 is designed as a friction wheel drive,wherein a drive shaft 56 of a rotary motor 55 extends to the base 5′parallel to the support axis of rotation 3 with an offset relative tothe support axis of rotation 3, wherein on the output section of thedrive shaft 56, for example, an idle wheel 57 implemented with a rubberring is arranged, which rolls off along a circular symmetric bearingsurface 58 of the base 5′.

Due to the compact design, in particular the short axial vertical axis54, here the radial extension 59 of the vertical axis is chosen as largeas possible and the drive shaft 56, respectively the idle wheel 57, runson a bearing surface 58 defined by the inside of a base ring.Alternatively, the drive can also be designed in such a way that thedrive shaft 56 is arranged outside of a base ring, so that it rolls offon an outer side of the base ring of the base.

In a specific embodiment, the laser scanner has a total of only onepower supply unit, namely the power supply unit for the active driveelement 55, which is arranged in the support 4, wherein the base 5′ ispermanently and irreversibly electrically decoupled from the support 4and no electrical power transmission takes place between the support 4and the base 5′.

The FIGS. 13 a,b show two embodiments of a mounting according to theinvention of an axially compact vertical axis, in other words of anaxial vertical axis which is short compared to the radial extension 59.In each of the examples shown the laser scanner is placed, for example,on a table 18.

Due to the axially compact (short) design the vertical axis along thesupport axis of rotation 3 has exclusively one short overall effectivestabilization region 15, by means of which a stabilization of thesupport 4 is obtained with respect to a tilting of the support 4relative to the base 5, or the support axis of rotation 3. In order toprevent a tilting of the support 4 relative to the base 5 therefore,according to the invention the substantially radially symmetricextension 59 of the vertical axis, perpendicular to the support axis ofrotation 3, is greater than its axial extension.

In accordance with one aspect of the invention, the support 4 is alsomounted on the stabilization region 15 of the base 5 with a singlebearing rim such that it can rotate about the support axis of rotation,the stabilization being obtained exclusively by the single bearing rim.

The bearing rim can be designed as a single-row four-point rollerbearing 60 with a rolling body 66 (FIG. 13 a ) or as a single-rowsliding bearing 61 with an outer 62A and inner ring 62B (FIG. 13 b ),wherein the outer ring with the inner ring forms two contact bearings63A,B axially spaced apart with respect to the support axis of rotation3. For example, one contact bearing 63A can be arranged elastically 67,to ensure sufficient play for the rotation around the support axis ofrotation 3.

The stabilization can then be generated, for example, by means of aspring tension acting radially on the bearing rim with respect to thesupport axis of rotation 3.

A further aspect of the invention is aimed at ensuring that bearinglubricants cannot escape from the bearing into other parts of the laserscanner. This is important, for example, in a drive unit according tothe invention designed as a rotary motor 55 with a drive shaft 56 offsetwith respect to the support axis of rotation 3 and with an idle wheel 57implemented with a rubber ring (see description for FIG. 12 ) for therotation of the support 4 about the support axis of rotation 3, becausedue to lubricants, for example, the adhesion of the idle wheel 57 on thebase ring 58 is reduced (see FIG. 12 ).

On the one hand, this can be achieved by, for example, the mountingbeing implemented as a four-point roller bearing in the form of adry-running ring bearing with ceramic roller elements.

On the other hand, for example, along a boundary region substantiallyparallel to a contact bearing a lubricant-repellent emulsion can beapplied, so that any dispersion of a lubricant due to the surfacetension of the lubricant-repellent emulsion is substantially limited bythe boundary region.

FIGS. 14 a,b show a mounting 13 according to the invention and a compactdrive unit according to the invention of the beam steering unit 7 aboutthe fast axis by means of a bell-shaped element 68.

FIG. 14 a shows the beam steering unit 7, which is connected to a shaft69 mounted 13 in the support 4 along the beam axis of rotation, inparticular wherein the shaft 69 penetrates into the beam steering unit 7with a defined penetration depth or is designed integrally with the beamsteering unit 7. The shaft 69 is also connected to a bell-shaped element68, wherein the bell-shaped element 68 defines a bell-shaped body 70 anda bell-shaped back 71 (see FIG. 14 b ). In the bell-shaped body 70 apassive magnetic element 72 is arranged, which is connected to thebell-shaped element 68, and an active drive element 73 is arranged onthe support 4 to generate an electromagnetic interaction with thepassive magnetic element 72, for example an electrical coil element,wherein the active drive element 73 protrudes at least partly into thebell-shaped body 70, so that by a radial interaction between the activedrive element 73 and the passive magnetic element 72 the beam steeringunit 7 can be set into a defined rotational movement about the beam axisof rotation.

For a maximally compact design, for example the whole of the activedrive element 73 and at least part of the mounting bush 74 for themounting 13 of the shaft 69 in the support 4 are arranged in thebell-shaped body 70, in particular wherein the bearing is implemented asa roller bearing and rolling bodies 66 of the rolling bearing protrudeat least partially into the bell-shaped body 70. In addition, a part ofthe mounting bush 74 can protrude into the beam steering unit 7, inparticular wherein parts of the rolling bodies 66 of the roller bearingat least partially protrude into the beam steering unit 7.

A further aspect of the invention relates, for example, to the fact thatthe shaft 69 comprises only one single effective stabilization region15′ axially along the beam axis of rotation, which is used to stabilizethe support against a tilting of the shaft 69 relative to the support 4,or to the beam axis of rotation, wherein the beam steering unit 7, thebell-shaped element 68 and the shaft 69 are designed and arranged withrespect to each other (for example, including by means of balancingelements) in such a way that their common center of gravity 75 axiallyalong the beam axis of rotation is located in the stabilization region15′, in particular wherein the stabilization is achieved exclusively bya bearing which substantially axially-symmetrically surrounds the centerof gravity 75.

FIG. 15 shows a further embodiment of the inventive bell element 68′,wherein here an encoder disc 76 is arranged on the bell-shaped back, inparticular integrated or forming a single piece with the bell-shapedelement 68′, for recording angle encoder data with respect to therotation of the beam steering unit 7 about the beam axis of rotation bymeans of an angle encoder 12′ arranged in the support 4.

The FIGS. 16 a,b show an inventive coupling of a beam steering unit 7 tothe shaft 69 along the beam axis of rotation by means of compressiblestabilization elements 77 in the coupled and uncoupled state.

FIG. 16 a shows the uncoupled beam steering unit 7, which comprises amirrored surface 14 for deflecting the distance measurement radiation,in particular a tilted mirrored surface with respect to the beam axis ofrotation. Typically, on account of the high centrifugal forces inducedby the rapid rotation of the beam steering unit 7, the mirrored surface14 is implemented integrally with the beam steering unit.

The beam steering unit 7 has an enclosure region 78 for a penetration ofthe shaft 69 during a coupling of the beam steering unit 7 to the shaft69, so that in the coupled state between the shaft 69 and the enclosureregion 78 of the beam steering unit 7 a gap 79 with a defined width ispresent (see FIG. 16 b , which shows the beam steering unit 7 in thestate where it is coupled to the shaft 69). The enclosure region 78 alsohas a stabilization element 77 that can be compressed in the gap 79 fortolerance compensation and for the stable connection of the beamsteering unit 7 to the shaft 69, wherein in the uncoupled state thestabilization element 77 has a thickness that is greater than the widthof the gap 79 and in the coupled state surrounds the shaft 69, forexample in a continuous annular manner.

In accordance with one aspect of the invention, the beam steering unit7, the shaft 69 and the stabilization element 77 are designed andinteract in such a way that during the coupling of the beam steeringunit 7 with the shaft 69 the stabilization element 77 arranged betweenthe enclosure region 78 and the shaft 69 is compressed and in thecoupled state is present in the gap 79 in such a deformed state, inparticular wherein at least a portion of the stabilization element 77 isplastically deformed, that only small residual elastic forces act on thebeam steering unit 7 and the shaft 69 radially to the beam axis ofrotation; and the beam steering unit 7 and the shaft 69 are stabilizedin relation to each other in the axial direction with respect to thebeam axis of rotation, the beam steering unit 7 is stabilized against atilting relative to the shaft 69 over a stabilization region 15″ definedby the length of the penetration region, and the residual elastic forcesdo not act on the mirrored surface 14 apart from a defined tolerancerange, to the extent that the residual elastic forces on the mirroredsurface 14 are so small that a high surface accuracy of the mirroredsurface 14 is maintained.

The stabilization element 77 can be implemented, for example, in anannular shape and from a material with homogeneous plastic properties,for example, a homogeneous plastic flow range, wherein the stabilizationelement 77 is integrated into the beam steering unit 7, for exampleinjection molded on the beam steering unit 7.

In addition, the beam steering unit 7 and the shaft 69 are typicallyglued 80 to each other as part of their coupling, wherein for excessadhesive or for applying the adhesive, defined openings 81 or accessports are provided in the beam steering unit 7.

The FIGS. 17 a,b show an arrangement according to the invention of alaser scanner using a skeletal, three-part support 4′ and a base 5,wherein the support 4′ here is formed by means of a skeletal structureconsisting of three separately detachable support structures 82,83A,B,which are coupled to each other, for example, by means of a connectionbased on normal pins. FIG. 17 a shows the individual elements of thesupport 4′ and the base 5, whereas FIG. 17 b shows the assembledelements.

A central support structure 82 is mounted on the base 5 coaxially withthe support axis of rotation 3 and two further separate supportstructures 83A,B are connected to the central support structure 82, butnot to the base 5, wherein the beam steering unit 7 is arrangedexclusively in one of the other support structures 83A. In particular,the central support structure 82 defines a vertical axis 84 with aneffective stabilization region 15′″, by means of which a stabilizationof the further support structures 83A,B is obtained against tilting ofthe support structures 83A,B relative to the vertical axis 84 and thusto the support axis of rotation 3. The vertical axis 84 furthercomprises two holders 85A,B for receiving and coupling the further, inparticular, plate-like support structures 83A,B.

Such a design of the support 4′ allows, for example, a modulardeployment of the laser scanner, in particular with regard to servicing,in other words, maintenance or replacement of individual modular parts,or in terms of upgrade capabilities of the laser scanner. For example,the support structures can be designed in such a way that one supportstructure 83A receives the beam steering unit and another supportstructure 83B receives the distance measuring device 10, so that thesetwo core elements of the laser scanner are each interchangeable in amodular fashion.

In order to ensure sufficient axial positional stability despite theskeletal structure, in particular in terms of tilting of the supportstructure 83A carrying the beam steering unit 7 with respect to thesupport axis of rotation 3, the support structures 82,83A,B, and inparticular the two further support structures 83A,B, are each formed,for example, by means of an all-aluminum housing 86A,B (indicated by thedashed line in FIG. 17 b ), which additionally rests, for example,directly on a horizontal surface 87 of the central support structure 82.

FIG. 18 shows a typical reference element 88 in the support 4″ for theadjustment and/or calibration of the distance measuring device, forexample, for an intensity, contrast and/or distance reference.Typically, the reflectivity and/or color of the reference element 88 canvary with the beam direction of rotation defined by the rotating beamsteering unit 7, for example, to enable a dynamic distance and intensitycalibration. In the example shown the reflectivity of the referenceelement 88 varies in three fixed levels. Alternatively, a referenceelement unit with a reflectivity gradient and/or with a color gradientcan also be used.

The distance measuring unit and the scanning can be based both on asingle distance measurement beam and on a plurality of distancemeasurement beams emitted at the same time.

FIG. 19 a and FIG. 19 b show a laser scanner according to the invention,wherein the distance measuring unit and the scanning are based on amulti-beam scanning pattern 89,89′, for example of a plurality ofdistance measurement beams emitted at the same time. This has theadvantage, for example, that with a lower rotation speed of the beamsteering unit about the fast axis a higher point rate and/or a higherpoint density is achieved. For example, instead of a single distancemeasurement beam a beam fan 9′ can be used consisting, for example, offour adjacently arranged single beams, each with a small divergence.

For example, the individual beams are generated by an electronicdistance measuring module arranged in the support 4 with a plurality oftransmission beams and aimed at the beam steering unit 7, for examplewith a divergence of less than 15 degrees between the individual beams.For example, the beams are aligned in such a way that during thescanning process, in a scanning region near to the horizontal scanningplane (the plane perpendicular to the beam axis of rotation 3 andsupport axis of rotation 6), substantially similarly oriented scanningpatterns 89,89′ are generated in each case by the individual beams, forexample, a scanning line, in particular, a smooth horizontal scanningline 89 (FIG. 19 a ) or a substantially—formed in FIG. 19 b by sixscanning points—horizontal scanning line 89′ (FIG. 19 b ) withalternating vertically offset scanning points. Alternatively, theindividual beams can be emitted in such a way that they form complextwo-dimensional scanning patterns.

At least in a defined scanning region, for example near the horizontalplane, the beam fans 89,89′ can be emitted in such a way that, duringthe rotation of the support 4 and the beam steering unit 7, for examplecomplementary scanning lines or overlapping scanning lines aregenerated. The point density rises toward the zenith, where, forexample, the individual scanning points, respectively scanning lines,increasingly overlap. The rotation of the scanning pattern (90 degreesof rotation with respect to alignment to the horizon) andover-determination of the 3D point cloud in the zenith can be allowedfor by means of appropriate data reduction and/or data selection, forexample. In addition, the rotation speeds of the support 4 about thesupport axis of rotation 3 and of the beam steering unit 7 about thebeam axis of rotation 6 can be synchronized, for example to optimize thescanning with respect to scan traces.

FIG. 20 a,b shows a receiving element 90 for receiving the base 5″ of alaser scanner, for example, for attaching the laser scanner to a tripod,wherein the receiving element 90 can be detached from the base 5″ bymeans of a latching device. FIG. 20 a shows the receiving element 90 inthe state uncoupled to the base 5″ and FIG. 20 b shows the receivingelement 90 in the state coupled to the base 5″.

The latching device comprises a cutout portion 91 on the base 5″, intowhich a ring 92 is recessed, which ring 92 in its interior has acircumferentially continuous cavity, and on the receiving element 90comprises a spigot 93, wherein the spigot 93 comprises at least threelatching bodies 94, which in a basic position of a release devicecomprising a radial pin 95A, an axial pin 95B and a spring 96 pushradially outwards, for example by means of a tensioning spring, in orderto block the detachability of the receiving element 90 from the base 5″by the fact that the latching bodies 94 engage in the cavity of the ring92. In order to release the receiving element 90 from the base 5″,activating the release device enables the latching bodes 94 to radiallyescape into the spigot 93.

It goes without saying that these figures illustrated only show possibleexemplary embodiments in schematic form. The different approaches canalso be combined with methods from the prior art.

1. A laser scanner for optical measurement of an environment, comprisingan optical distance measuring device for detecting distance measurementdata, having a transmitter unit for emitting a distance measurementradiation and a receiver unit for receiving returning parts of thedistance measurement radiation, a flat sensor for detecting surfacesensor data, in particular, at least one color camera for recordingimage data, wherein the sensor defines an optical axis of the sensor anda viewing direction of the sensor along the optical axis, a support, abeam steering unit for the distance measurement radiation, which isfixed to the support such that it can rotate about a beam axis ofrotation, in particular a fast axis of rotation, an angle encoder forrecording angle data with respect to a rotation of the beam steeringunit about the beam axis of rotation, wherein the distance measurementdata, the surface sensor data and the angle data, hereafter designatedas measurement data, are detected during a measurement process whichcomprises a scanning sampling by means of the distance measuring devicewith a defined progressive, in particular continuous rotation of thebeam steering unit about the fast axis of rotation, and a continuousemission of the distance measurement radiation and a continuousreception of returning parts of the distance measurement radiation, andperforming multiple readouts of the surface sensor with respect todifferent viewing directions of the sensor, wherein a central referencepoint of the laser scanner is defined as the origin for distance andangle measurement, in particular by the intersection point of the beamaxis of rotation with a support axis of rotation for a rotation of thesupport about a base, the surface sensor is fixedly arranged on thesupport with a stationary field of view relative to the support andfacing away from the support, in the sense that the field of view of thesensor changes during the measurement process only in the event of amovement of the support, in particular a rotation of the support aboutthe beam axis of rotation, and a virtual backwards extension of theoptical axis of the surface sensor passes through the central referencepoint.
 2. The laser scanner as claimed in claim 1, wherein amultiplicity of surface sensors is arranged on the support, wherein foreach one of the multiplicity of surface sensors the virtual backwardsextension of its optical axis substantially passes through the centralreference point.
 3. The laser scanner as claimed in claim 2, wherein bymeans of a virtual 360-degree rotation of the beam steering unit aboutthe beam axis of rotation a scanning plane of the distance measurementradiation is defined, and one of the multiplicity of surface sensors isarranged in such a way that its visual field cone intersects thescanning plane, in particular wherein the support is fixed on a basesuch that it can rotate about a support axis of rotation, in particulara slow axis of rotation, and the visual field cone of the surface sensorintersects with the steepest elevational orientation of the optical axiswith a virtual extension of the support axis of rotation.
 4. The laserscanner as claimed in claim 3, wherein the support is fixed such that itcan rotate around a support axis of rotation, in particular a slow axisof rotation, the laser scanner comprises a further angle encoder fordetecting further angle data as measurement data relating to a rotationof the support about the support axis of rotation, the measurement alsocomprises multiple readouts of the multiplicity of surface sensors withrespect to different azimuthal viewing directions of the individualsensors, and the multiplicity of surface sensors is arranged in such away that during the measurement process they enable a full-domemeasurement, in particular wherein the visual field cone of the surfacesensor intersects with the steepest elevational orientation of theoptical axis with a virtual extension of the support axis of rotation,wherein the multiplicity of surface sensors define a minimum detectionradius for the full-dome measurement in such a way that by the centralreference point and the minimum detection radius a spherical surface isdefined with the central reference point at the center, and during themeasurement process at least one hemispherical surface defined by thespherical surface can only just be scanned by the multiplicity ofsurface sensors, in particular, wherein by means of the multiplicity ofsurface sensors a partial surface of the sphere can be scanned that islarger than the hemispherical surface.
 5. The laser scanner as claimedin claim 1, wherein by means of a virtual 360-degree rotation of thebeam steering unit about the beam axis of rotation a scanning plane ofthe distance measurement radiation is defined, and the surface sensor isarranged on the support and oriented in such a way that its azimuthalviewing direction and the azimuthal orientation of the scanning planeare different, such that a virtual backwards extension of the opticalaxis of the surface sensor cuts the scanning plane under a definedcutting angle, in particular wherein the cutting angle is at least 45degrees, in particular wherein the scanning plane is not captured by thefield of view of the surface sensor.
 6. The laser scanner as claimed inclaim 5, wherein the laser scanner is configured to carry out a fullyautomated first pre-programmed measurement process with defined stepsaccording to the following temporal sequence: recording of surfacesensor data comprising rotation of the support about the support axis ofrotation, and reading out the surface sensor for detecting surfacesensor data, in particular, wherein an initial processing and display ofthe surface sensor data is carried out, recording of scanningmeasurement data, namely distance measurement data and associated firstand second angle data, comprising, rotation of the support about thesupport axis of rotation, rotation of the beam steering unit about thebeam axis of rotation, and emitting the distance measurement radiationand receiving returning parts of the distance measurement radiation fordetecting distance measurement data, wherein associated first and secondangle data are detected during the detection of distance measurementdata.
 7. The laser scanner as claimed in claim 6, wherein the laserscanner is configured to carry out an at least initial processing ofparts of the measurement data during the measurement process, inparticular linking of the scanning measurement data and the surfacesensor data, wherein the display of portions of the processedmeasurement data takes place continuously during the measurement processand is progressively, in particular continuously, updated based on theprocessed measurement data, in particular supplemented and/or replaced,specifically wherein a display coupled or integrated with the laserscanner is provided for the display.
 8. The laser scanner as claimed inclaim 6, wherein the laser scanner is configured such that during themeasurement process a complete detection of all surface sensor datarequired for the measurement process first takes place before thedetection of scanning measurement data, wherein based on the detectedsurface sensor data a 2D panorama display of at least one partial regionof the environment is generated, or a 2D full-dome projection isgenerated.
 9. The laser scanner as claimed in claim 3, wherein themultiplicity of surface sensors is arranged with the same azimuthaldirection, wherein the optical axes of the multiplicity of surfacesensors are arranged in a plane outside the scanning plane.
 10. Thelaser scanner as claimed in claim 9, wherein the visual field cone ofthe surface sensor with the steepest elevation orientation of theoptical axis intersects with the scanning plane at a distance of between0.25 and 7 m from the central reference point.
 11. The laser scanner asclaimed in claim 1, wherein the laser scanner comprises a lamp whichilluminates the field of view of the surface sensor, in particular, oneor more LEDs, wherein the lamp defines an optical axis of the lamp andan illumination direction of the lamp along the optical axis of thelamp, and the laser scanner is configured that the lamp is used for aselectively controllable illumination, substantially directed onto thefield of view of the surface sensor.
 12. The laser scanner as claimed inclaim 11, wherein the lamp is arranged on the support directly next tothe surface sensor, in particular with a maximum lateral offset betweenthe optical axis of the lamp and the optical axis of the surface sensorof 4 cm, and/or the lamp substantially emits white light, which meansbroadband light in the visible wavelength range, in particular by thelamp being designed as a dual LED, namely an LED couplet with twoseparate LEDs differing with respect to their emitted spectral range.13. The laser scanner as claimed in claim 11, wherein the laser scanneris configured such that a first set of surface sensor data is detected,in particular surface sensor data with reduced resolution, based on thefirst set of surface sensor data a set of illumination settings for thelamp is derived, and based on the set of illumination settings, a secondset of surface sensor data is recorded, in particular wherein the firstset of surface sensor data is detected without using the lamp or using auniform illumination by the lamp.
 14. The laser scanner as claimed inclaim 1, wherein the support is implemented by means of a skeletalstructure, the support comprises a cover carried by the skeletalstructure and detachable therefrom as a shell element, and the surfacesensor is secured to the shell element and carried by the shell element,in particular wherein for the case that the laser scanner comprises amultiplicity of surface sensors, each thereof being mounted on the shellelement individually and carried separately by the shell element, in thesense that each surface sensor of the plurality of surface sensors iscarried separately and in each individual case by the shell element. 15.A measuring system for optical measurement of an environment, having alaser scanner according to claim 1, a processing unit for processingportions of the measurement data into processed measurement data, and adisplay unit for a defined display of portions of the processedmeasurement data, which represent at least a partial region of theenvironment, wherein an infrared sensor sensitive in the infraredwavelength range is integrally arranged on the support, wherein theinfrared sensor defines an optical axis of the infrared sensor and aviewing direction of the infrared sensor along the optical axis, and aposition of the infrared sensor and an orientation of its optical axiswith respect to the beam steering unit and the central reference pointis known, and the laser scanner is configured such that the measurementdata comprise infrared data detected with the infrared sensor and themeasurement data can be associated with the infrared data, in particularso that the display of portions of the processed measurement data isgenerated in the form of a colored 3D point cloud and the temperatureinformation are stored in the 3D point cloud and/or displayed with adefined color coding.